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    Weil McClain Boiler Question (26 Posts)

  • dvizz dvizz @ 1:40 PM
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    Weil McClain Boiler Question

    I have a GV-5 series 1 WM Gold boiler that is connected to a WM Combo 30 indirect. The water stops circulating to my baseboards when the boiler is supplying hot water to the combo 30 . There is a 3 way valve coming from the boiler supply diverting flow from the riser going to the base board feeds to the combo 30. I have 4 zones and during the past few weeks could not figure out why the baseboards are cold even though the room stats are calling for heat. I have 4 Taco circulating pumps and 4 Honeywell zone valves. I have a temp. setting of 160 cut in to 190 cut out on the WM boiler. I raised the DHW temp this winter to allow hot water to reach our shower located at the other end of our rancher. This causes the indirect to take longer to reach HW temp. causing the base boards to not get flow. I've read various discussions on close space t's configurations but would like to see a diagram of how that piping would be run.
    This post was edited by an admin on March 5, 2014 2:55 PM.
  • heatpro02920 heatpro02920 @ 8:34 PM
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    Can you post pictures

    That would help me see what you are saying, I think I got it but a picture would keep me from sounding like a jerk {more than normal anyway}...
  • dvizz dvizz @ 8:24 AM
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    Weil McClain Boiler Question

    I'll take some photos and try to figure out how to attach them. Basically the supply is a 1" line coming out the side of the boiler. There is a 3 way valve at the elbow where the riser travels up to the ceiling and elbows across to the 3/4" line branches where the 4 Taco circulating pumps feed the baseboard zones. The zones all are controlled by honeywell zone valves on the returns.
    The indirect mounted next to the boiler is being fed from the 3 way valve and it returns back to a 1" riser coming back from the baseboard zones. When the indirect calls for heat, the 3 way shuts off the flow to the baseboard. The Taco pumps still run even though they are not getting fed from the boiler. There is an internal Taco pump factory mounted on top of the boiler which runs whenever the indirect calls and the baseboard zones are calling. I think the installer did not pipe the system correctly as this cold winter has caused the room temps to be below set point as the indirect is taking the hot water supply to maintain it's temp.
  • dvizz dvizz @ 8:36 AM
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    Weil McClain Boiler Question

    Here are some photos of my system. It was suggested I remove the zone valves and go with flow control valves. The 3 way valve is closing the flow up through the riser until the indirect is satisfied. There is a circulator pumping water to the indirect and it also runs when the zones call for heat. I need to pipe the system differently, so the indirect is it's own zone and will run in series with the zones.
  • icesailor icesailor @ 9:11 AM
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    Zone Valves:

    Nice neat install.
    If someone doesn't understand the problem I am writing about, they won't understand why you are having a problem. The last one I dealt with was installed in 2000 or before. The owner never told me about the problem they started having. They always called the gas company.
    Take the top cover off the boiler. You will see that black painted valve with the plug in it sticking up between the two outlet pipes. Make the boiler run. Feel the pipes as they heat up. The boiler and the outlet should rise together. Reach down and feel the 3/4" nipple that connects the valve to the lower pipe. That's where the water is bypassing. The boiler will get hot but the water will either bypass through the hole or not. That's where the problem is. When the problem started occurring, and they couldn't get parts to repair the valve, Series 3+ switched to P/S piping inside the boiler because some installers didn't install the second circulator or something like that.
    Its the same as a failed thermostatic element on a Watts 70A hot water extender valve on a tank-less coil. If it is broken, the only repair is to replace it.
    As piped, you could easily re-pipe that like a Munchkin with P/S piping to the house, but if the problem doesn't go away, you still have to address the valve not working properly.
    I don't understand the need for that 3-way valve. It could be compounding your problem.
    This post was edited by an admin on March 7, 2014 9:29 AM.
  • dvizz dvizz @ 10:36 AM
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    Weil McClain Boiler Question

    I want to remove the 3 way valve and pipe the system using closely spaced T's I also would like to replace the Honeywell zone valves with flow control valves. The illustration shown for adding a circulator , check valve and closely spaced t's was shown to me by another site. Will this work? or are there other options?
    This post was edited by an admin on March 7, 2014 10:36 AM.
  • icesailor icesailor @ 11:49 AM
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    Flow Checks/Zone Valves:

    A Zone Valve is a motorized Flow Check.
    Almost every Munchkin I have ever seen installed when your boiler was installed was installed like that (yours). Without the 3-way. They worked fine.
    If you have a bad thermostatic mixer, I don't care how you pipe it. It isn't going to work any differently.
    Weil-McLain had another GV, maybe Series 2 which they shipped with a second circulator and you were supposed to pipe it as Primary Secondary. Some installers kept the second circulator and uses the boiler pump inside as the system pump. They worked. The ones with the broken thermostat didn't work. It all depended on where the plunger of the thermostat stopped when it failed. If it blocked the hole in the bottom, the boiler worked. If it wasn't covering the hole, it didn't work. There are varying degrees in between. The problem was so bad that they modified the internal piping and put both circulators inside. The primary loop was inside the boiler.
    You wouldn't know about the thermostat unless I had told you. You had others look at it. I keep forgetting what my electrician friend always used to remind me. "They're smart, we/I'm not". Try the circulators and re-piping it. If it doesn't work, maybe they'll get smarter and look at that thermostatic valve inside. I have history with those boilers. Do they?
    The only thing that the 3-way valve does in your system does is that it either makes the water go through the indirect, or into the system. It can't do both. That is your priority. Did they tell you that?
  • dvizz dvizz @ 1:14 PM
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    Weil McClain Boiler Question

    Thanks for the input. I plan on opening up the mixing valve tonight when I get home. The boiler was installed in 97 so there is a good chance the mixing valve isn't working right. Do you see the way the supply and return coming off of the boiler are piped into the return side riser? Will this piping allow the water returning flowing down the riser to continue to the return T piped above the supply T? It looks like the return water will just loop around as its being pulled by the zone pumps. I hope you can understand my point.
    This post was edited by an admin on March 7, 2014 1:16 PM.
  • icesailor icesailor @ 2:45 PM
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    Tech Bulletin:

    Did you read the tech bulletin about the temperatures? Did you understand that the boiler will be ruined by condensation if you don't fix it? And that you must run it so it doesn't condense anymore?
    Give yourself some time because it isn't an easy fix if the plug doesn't come out.
    There is absolutely nothing wrong with the piping of your boiler. Almost anything will work. Fix that before taking on any other projects in piping.

    Which made me realize something that is related but I didn't realize until now.
    Years ago, I had a friend who was young and in the HVAC business, He used to stop and pick my brain. I used to pick his. One day I was driving down a dirt road and we passed. He stopped to show me the boiler he had in the back of the truck, completely rusted out. Worthless, a big pile of rust. It was a GV boiler. Maybe a 5 or 6. He asked me what I thought had happened to it. I had no idea. It had been used to heat a pool plate heater. It had been running for 3 years and had failed. From condensation.
    That guy now works for a well known plumbing, heating and mechanical guru we all know.
    After this discussion and reading the Weil-McLain tech bulletin, and the fact that it was a series 1 or series 2 boiler, the thermostatic mixer had failed and because it could never catch up with the pool plate heater, the boiler condensed itself to death. There was nothing wrong with the boiler or the piping. Just the mixer valve that is supposed to bypass water until the boiler water is over the dew point. The one that I had dealings with recently had big goobers of rust in the exhaust piping. I hate to think of what it was like before it was fixed. The "fix" is a Band-Aid. You can't use ODR. If you want to play with pipes, install a Taco "I" series 4-way mixer and that will protect the boiler. and you can use ODR.
    But that's my opinion and not worth much.
  • STEVEusaPA STEVEusaPA @ 9:50 PM
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    How is it controlled?

    Just wondering if the domestic hot water is set for priority.
  • dvizz dvizz @ 9:45 AM
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    Weil McClain Boiler Question

    There is no priority control as wired. The indirect aquastat will open the 3 way valve whenever it is demanding heat, which closes flow to the baseboards. The baseboard circulator pumps will continue to run in that state.
  • icesailor icesailor @ 6:53 AM
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    GV-5 Series 1:

    If its a Series 1, the thermostatic part of the 3-way may have failed and won't mix properly. There is an old tech bulletin from Weil-McLain on how to fix it.
    You may not find the bulletin on the W/M website but they will say that the part is obsolete and unavailable. The fix involves getting the top of the black 3-way valve off and removing the broken thermostat. You then drive the appropriate copper cap into the hole inside the fitting. The plug is one of two sizes, You won't know until you get the top off. Primary/secondary piping will not solve the problem. You have to fix this first. I've never personally repaired one. I've just had customers and other plumber friends that had the problem. And the gas service company was expert in fixing them.

    Someone here may have more pointers. The gas provider made some sort of tool to get the plug out of the top of the 3-way. You can't get a wrench on it. You don't need to dismantle the piping to do the repair.
    All the ones, and the last one I worked on had the Priority Switch on the zone controller OFF. You couldn't get really hot water into the indirect, no matter how long it ran. The boiler was hot, but it was circulating internally.
  • dvizz dvizz @ 8:30 AM
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    Weil McClain Boiler Question

    Are you describing the 3 way mounted outside the boiler?. That valve is not mixing, just opening and closing flow to the indirect or the baseboards.
  • icesailor icesailor @ 11:06 AM
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    The mixer valve that I am referring to is item #1 on page 27 if the Series 1 Installation and Operating manual.
    If that doesn't work properly, nothing works properly.
    You may have an additional 3-way mixer. That's not what I am talking about.
    A GV-5 usually doesn't ever need the DHW priority switch on. They have plenty of nuts for making hot water and heating at the same time.
  • dvizz dvizz @ 1:06 PM
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    Weil McClain Boiler Question

    You may have touched on one of the symptoms of my boiler. The domestic hot water indirect seems to take forever to reach temp. At times, raising the aquastat a touch results in the boiler pumping water to the indirect for longer than you would expect. I downloaded the WM SB0401R1 and see the fix for the unavailable WM part. You are saying I'll have trouble removing the spring and element without an appropriate tool? Also, what will the pump be pumping once the plug is installed replacing the element. It looks like the return will go directly to the boiler and no longer flow through the circulating pump?
    This post was edited by an admin on March 6, 2014 1:28 PM.
  • icesailor icesailor @ 4:03 PM
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    Weil-McLain has a tech bulletin on it.

    Weil McLain has a Tech Bulletin on it. You would probably have to contact them.
    There is someone here on The Wall who doesn't read often. I can find out what name he goes by on The Wall. He has probably changed more than anyone. You could contact him. He'll tell you what I have just said.
    If you look at page 22, it shows the part as #1. It has a plug on top. It is either a 3/4", 7/8" or 1" square drive. A 8 Point socket and extension will remove it. When you get the plug out, you remove the thermostatic operator. Once out, there will be a hole in the bottom of the fitting. Look at the picture. There is a 3/4" pipe nipple connection. You do NOT have to remove any part of the piping. Just jam the appropriate size copper cap, upside down into the hole. It stops the water from short cycling through the hole. That's the fix. That's the fix that Weil-McLain came up with and it was successful.
  • icesailor icesailor @ 12:02 PM
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    Here's the part, Here's the Tech Bulletin:

    Here's the part and a photograph:
    Here's the Tech Bulletin:
    I don't make this stuff up.
    If Techs would stop trying to re-invent the world by reading and contacting manufacturers technical support, life would be a lot easier.
    If you called me and I told you that you need to fix the thermostat, and you called someone else for an opinion and went with their ideas, and it was wrong, you would never call me back.
    I'm glad I'm retired now so I don't have to deal with the BS of experts that want to completely re-pipe a system that worked fine, then stopped working. If the piping was OK 20 years ago, and it suddenly stopped, what changed?

    You never learn HOW to fix it if you don't learn WHY it isn't working.
    This post was edited by an admin on March 7, 2014 12:14 PM.
  • Nat Nat @ 9:56 PM
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    Block Bypass valve

    Icesailor is correct. The Thermostatic mixing valve loses it's ability to allow boiler water to flow out of supply side properly once boiler is warmed up. This issue litterally will drive a heating person nuts. You first think there is air in the system. You purge zones and no air and scratch your head why the water isn't flowing through the zones. About 5 years ago I discovered the problem is the Thermostatic-bypass-valve. You don't need the valve at all unless you have an extremely large volume of water like a mono-flow loop in a hotel or an old black iron large system. Typical 3/4 copper systems don't need this valve. So in order to plug the bottom of the valve, you will need 1 large 36" pipe wrench and a 24" crescent wrench. Drain water down and heat the plug at the top of the valve and carefully get your pipe wrench in good position to "back-up" the valve housing and try to loosten plug. It can be tough to remove. Then remove guts and plug bottom bypass hole with copper cap or brass fitting you can drive into hole with a punch. It can be crude as long as hole is generally plugged off. Put cap back on and boiler will work like a champ.... I have probably done a dozen or more. There is no other solution to this problem. The new GV's have 2 circulators to perform what the thermostatic valve once did. By performing this task, you are essentially making the bypass valve into an elbow or coupling. I've found that the older blue colored valves are tougher to get apart. The newer black ones are easier.
    This post was edited by an admin on March 7, 2014 10:03 PM.
  • dvizz dvizz @ 5:33 PM
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    Weil McClain

    I have the blue version. I''m looking to get a socket and have my son help to hold the valve body while I try to loosen the plug. The valve has a 3/4" nipple connecting the bottom to the top of the boiler. I think that would break off easily. Once I drain the boiler down to below the valve body, will I need to purge air from the system after I fill the system back up to 15 lbs.?
    This post was edited by an admin on March 8, 2014 5:46 PM.
  • icesailor icesailor @ 7:27 PM
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    Gettin' right down to it:

    You're determined to do something that many of us would pass on.
    If you insist, Go to a tool rental place and see if you can get an offset 24" pipe wrench. You will need it to back up whatever you use to try to turn the plug. If Nat says the blue ones are harder to get out, the blue ones are harder to get out. Do not try to do it alone. You will need two people and you both must pull and push equally on whatever you use to twist. It really is sort of an all day job for two experienced people. You need the below offset pipe wrench because you don't have room to get a normal wrench inside. I owned all sorts of odd wrenches and tools to do such jobs. I never knew how I would approach something until I started. I never started a project like that that I finished it the way I planned in the beginning. But, understand that you MUST have a 8 point or 4 point socket to fit the plug. Nat said he uses a adjustable wrench. If he is talking about a "Crescent" type wrench, it'll bust your knuckles and probably slip off the nut. It is probably a 1" square drive 8 point socket. If you use the proper socket, and a cheater bar, and use a heat wrench on the fitting, you might get it out. Plan ahead and you might make it. Don't plan it like changing a tire during a NASCAR race. Take your time.
    Be sure that you have the 1/2" copper cap to punch into the hole.
    If you plan ahead and really work at it, it will come right out without a fuss. If you rush it and hack it, you will break the fitting and be in a real mess. So, take it the easy way.
  • Nat Nat @ 8:45 PM
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    Blue bypass

    Hi Dviss. Glad to help. The blue Bypass has 1/2 black nipple on bottom. Once you lift and flip over control panel and let it rest on top of boiler-circulator, you'll be able to get in good position to loosen the plug. Yes, you should have 2 people and be in sync with each other to achieve maximum torque.Shut all supply and return valves before you drain boiler down. There is a boiler drain in front bottom of GV. You'll need a 90Degree washing machine hose.Then you must heat the top of bypass, preferably with acetelyne to assist in getting plug out. As I indicated, in my experience, the blue valve is tougher to get out than the black one that was used by Weil McClain after first series GV's. Don't get frustrated. It  may come out easier than I'm saying. I had one that I had to remove and put in a vice to get it apart. If you cannot get it out, I would get an experienced plumber. You will need a metal cutting blade and sawzall to cut the half inch nipple directly in the middle so each piece can be remove and plugged. The circulator flange bolts will need to be cut and the 1' copper inlet will need to be removed to get the whole thing out. Essentially you will be turning the Blue valve into a 90 degree elbow. Good luck. It will be worth the effort 
  • dvizz dvizz @ 6:00 PM
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    Weill McClain

    Thanks Nat. Appreciate the feedback.
  • dvizz dvizz @ 9:54 AM
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    Weil McClain Boiler Question

    Nat, I would like to do away with the 3 way valve located on the boiler supply. It shuts off flow to the baseboards and diverts flow to the indirect. You can see existing boiler piping on left and a repiping with the 3 way removed, closely spaced T's and circulator and flow control valve added. Based on your experience, how was the indirect piped without the 3 way? Does the piping using the CST"s and circulator look like it will work properly? I'm thinking when the zones call for heat, the flow from the returns will just circulate around in a loop.
  • icesailor icesailor @ 10:44 AM
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    Not speaking for Nat:

    Not speaking for Nat, fix the valve and see how it works. The 3-way valve acts as a "Priority Switch" on a zone valve controller.
    Trust me. There are a whole tribe of GV Series 1 and 2 that were ripped out because no one knew about the thermostat. That's why Series 3 and 4 had two pumps. GV's got a bad rap because of it.
    GV's were sort of the first US condensing type boiler. I consider them as "Bomb Proof". 
    Because I am hyper aware, I notice things and remember them. I always wondered where the rust chunks came from in some GV exhaust terminations. I have now figured out that they were Series 1 and 2 with failed thermostats. The rust chunks will plug up the passageways. No one will bother to clean them out because "You don't need to clean a gas boiler like you do an oil boiler".
    If the engine in your car was not running properly, and it needed a new thermostat because the engine didn't warm up properly and ran poorly for a long time in the cold, would you replace the thermostat or replace the motor?  
    Nat or I would give anything to have a boiler like you not jammed up against a wall on the right side so you had to get at the thermostat from the right side and have room to work. That's almost a gravy job. If the circulator under the top jacket stopped working, would you re-pipe it first and then see what happens?
    You must not realize what a nice clean professional installation you have. Re-piping your system isn't going to solve the problem.
    Re-pipe it. If that doesn't solve it, replace it.
    This post was edited by an admin on March 10, 2014 10:54 AM.
  • dvizz dvizz @ 8:18 AM
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    Weil McClain Mixing Valve

    I ended up having a local HVAC outfit show up Friday and take care of the mixing valve issue after trying to loosen it myself. Two guys tried to loosen the 1 1/2" plug on the blue mixing valve with wrenches and extensions, the thing wouldn't budge. They ended up sawzawing the pipes connected to the sides of the valve and spun the valve off of the 1/2" nipple threaded in to the bottom They re-piped the 1 " return to the circulating pump and capped the nipple that was getting flow through bottom of the mixing valve. The system is working much better now. The indirect aquastat is reaching temp. quicker and the baseboard zones are heating faster. To access the valve to allow cutting it out, we unplugged a couple of circuits and moved the control panel board mounted across the front of the boiler. Doing this allowed me to see how the mixing valve was piped. What was evident was the return water from the system was cycling through the mixing valve, some would flow in to the boiler but some would flow down through the bottom 1/2" nipple T'd to the supply line and go out without being heated. Good Fix.. Not knowing this, I previously replaced two Taco 07 circulators and bled the system several times trying to correct the cause of lack of hot water. Thanks for alerting me on this repair.
    This post was edited by an admin on March 17, 2014 9:41 AM.
  • icesailor icesailor @ 9:54 AM
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    Old Gold's:

    There are a lot of old GV Series 1 and 2 boilers in the scrap yard because of this.
    Its amazing how much better something works when it is fixed and working properly.
    IMO, its a good cast iron sealed combustion gas boiler. If the idea wasn't good, they wouldn't have come out with the GV 90+. The same boiler with stainless steel heat recovery exhaust. They'll never compete for the Mod/Con wall hung market. But they'll be like the Eveready Bunny. Still going.

    If Nat says the blue ones are harder to get out, the blue ones are harder to get out.
    I would have drilled a 1" hole with a Hole Saw down through the middle of the plug, taken a Sawzall or a Saber Saw and cut tree or mire slots in the plug towards the threads and popped the pieces out. After sticking a small rag through the hole to plug the hole in the bottom. After I got the plug out, I'd have picked out the filings and pieces with a magnet. Some say you can't do that. I have.
    This post was edited by an admin on March 17, 2014 10:11 AM.
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