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Joined on September 1, 2010

Last Post on September 15, 2014

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@ March 16, 2014 9:33 PM in Taco Zone Valve

Can you post some pics of the boiler and controls?

I Would Say...

@ March 16, 2014 9:02 PM in pool heater

Theoretically yes, but practically no.

Some questions: what's the btu requirement for the pool? Can the boiler meet that requirement? What will be done to protect the boiler from flue gas condensation and thermal shock? How much effort will go into a viable control strategy? How much would all this cost? Is the boiler heating domestic? If so, how?

I think once all that is determined, even if it would work, it would be much more feasible to install the right tool for the job: a pool heater.

Not like that

@ March 16, 2014 8:39 PM in Boiler Was Plumbed Wrong...

The circulator MUST draw through the mixing valve and pump out toward the manifold.

Also, the primary circ should pump away from the expansion tank, not toward it. As Zman said, this may not be critical in your installation, but the position of the mixing circ is.

I don't think that what he said about controlling slab temp completely register with you. It doesn't with most folks initially.

Let me explain: the slab is a high mass heat emitter; it's a huge rock that takes a long time to heat up and will continue to give off heat for hours after the heat to it is shut off. We call this the flywheel effect: it takes a lot to get it going and a lot to slow it down or stop it. It requires much lower water temps than staple up which is low mass. If supplied with water that is too warm, the slab will drastically over-heat it's zone because it will give off heat for hours after it's thermostat is satisfied.

The question then is: what temp is right for the slab? That answer depends on what the heat load is at any given outdoor temp. What's right at 45* won't be right when it's 25*, etc. The colder it gets, the warmer the water needed and vise versa. And I purposely use the term "warm water", not hot.

By using outdoor reset (ODR), the water temp is varied according to OD temp to give the precise water temp to the slab that is needed and prevent the flywheel effect. In fact, when the heating curve is properly set on the ODR control, the thermostat actually becomes unnecessary though I would leave it to act as a high limit. I have a radiant slab next door that we installed and commissioned this fall and it's been running all winter without a thermostat. My neighbor has confirmed that the temp inside stays a constant 68*.

The slab presents another concern: the issue of flue gas condensation that you mentioned. If the radiant system in your slab was done correctly, then it should not require more than 110* supply water temp, and that's stretching it. That means you would be returning 100* or cooler to the boiler. That will definitely cause flue gas condensation and possibly thermal shock to the boiler block.

The solution to both issues is the smart valve that Zman gave a link to. It will modulate the water temp based upon ODR and has provision to protect the boiler also. Variable speed injection mixing with ODR is the other option, but that would require some re-piping and an additional circ. Look up Tekmar 356 for more info on this. The IValve may be easier for you.

The issue of heat transfer plates that Z mentioned is also very important since the btu output of the staple up floor would be reduced by at least half without them. Hotter water would then be required to compensate if you don't have them. All This effects your control strategy and piping arrangement.

What I'm trying to say is that you need more than just some re-piping: you need some design work to determine the proper approach to correct whatever issues your system has. That all starts with a heat loss calculation. That's the foundation for everything.

I would recommend that you google "SlantFin Heat Loss Calculator" and download that. It's free and its self explanatory and simple to use. It will require taking measurements of your windows, doors, walls, floor space, etc. and entering the data in the program.

Once you have the heat loss calc and know approximately how much tubing is in your floors, a determination can be made upon how to proceed.

You get what you pay for

@ March 16, 2014 7:32 PM in system advice

I would not use any Chinese manifolds. They're junk. Why would you attempt to construct a Cadilac from Yugo parts?I've had two jobs where the customer supplied the manifolds (both Refeng) and they leaked like sieves. Since then, I insist on using ones that I provide - Rehau, Caleffi or Viega.The same goes for pex-al-pex. I wouldn't consider the Chinese stuff.There are photos somewhere on the site of the Chinese pex delaminating and blistering after a short time.If you're looking for all the features that good manifolds provide (individual circuit purging, flow control, balancing, etc.) then you'll find you're better of purchasing them than trying to construct them.

Nite Setback...

@ March 15, 2014 10:22 PM in GB-142 outdoor reset?

Is not a good idea with a mod/con that has OD reset. It is actually counter-productive to what the boiler programming is trying to accomplish and will result in decreased efficiency and comfort.

Get the OD reset curve set properly based upon an accurate heat loss calc and leave the thermostat at one temp. You cannot use both the RC10 and the AM10 together. You need a standard heating thermostat.


@ March 15, 2014 5:39 PM in GB-142 outdoor reset?

The AM10 controls outdoor reset and communicates with the boiler. The OD sensor must connect to th AM10.

I posted detailed instructions for this very recently for someone. Search my posts and you should find it.

The AM10 has nothing to do with the pumps.

The "PZ" terminals are for a domestic hot water re-circulation pump, not space heating. You can piggyback on to the "PK" terminals for a system circ provided that both circ's draw less than 5 amps combined.

All of this is in the applications manual for the 142. Are you using it? It sounds like you're fixing to make some serious mistakes with that boiler. Please, read the manual.


@ March 12, 2014 9:58 PM in Pumping away ? I must have something messed up! Help

And the laws of physics will outweigh the theories of physics every time.


@ March 12, 2014 6:09 PM in Sizing old cast iron water radiators that froze

Could anyone figure it without knowing how many sections? He needs to supply you that info.

Radiation tables

@ March 12, 2014 5:20 PM in Sizing old cast iron water radiators that froze

See the attached tables. Then multiply the square footage x 150 for 170* average water temp to get the btu output.

2 Boilers

@ March 11, 2014 10:36 PM in need some advice on how to size a new heating system in a remodel

I think you're on the right track.

Everything starts with an accurate heat loss calculation. SlantFin has a program that is easy to use and is free to download.

Sorry, but I don't have a link for it even though it's on my IPad. A simple search will find it for you.


@ March 10, 2014 8:56 PM in Legionnaire's found in heating system



@ March 8, 2014 6:17 PM in Sizing a boiler in Watertown, MA

I had some input with the design of this boiler and I'm impressed with what the engineers finally put into production. The ECR 97 GB is the same boiler with the added feature of being able to pipe out of it top or bottom and floor or wall mount.

The HX is a high grade SS helix coil, water tube. They promote it as self cleaning and the ones I've serviced were in perfect shape after running up to three years with no maintenance.

It has built in p/s with an on board UP15-42 circ on most sizes. Easy to install.

Check it out on the "Product of the Month" link below.

011 Circ

@ March 8, 2014 5:55 PM in Pumping away ? I must have something messed up! Help

The 011 circ is probably throwing too much pressure into the heat exchanger also.

The expansion tank will NOT "absorb" any pressure created by the circ. That's why it's connection to the system is called the Point Of No Pressure Change (PONPC). The tank will only receive the expanded volume of water that's created by heating it. So, whatever pressure differential the 011 is creating will effect the relief valve.

It may be a combination of BOTH an under-sized x tank and an over-sized circ on the primary.

If you have a 007 or 15-58 on hand, it would be relatively easy to swap out the primary circ and see how that effects your situation.

Regarding the X tank: you will not hurt the system by over-sizing it and you can hook multiple ones together at the same point for more capacity. Just make sure the air pressure on each bladder is the same with no pressure on the water side.

A Couple of Others

@ March 8, 2014 5:26 PM in Sizing a boiler in Watertown, MA

Utica/Dunkirk CSS 50k

T.T. 60k.


@ March 8, 2014 5:23 PM in Sizing a boiler in Watertown, MA

I'll add my two cents worth in concurring with what's been said. Size the boiler to the btu loss of the house, not the domestic. If you feel you need more domestic, then increase the size of the indirect. You won't have any faster recovery, but the additional storage capacity will give you more initially.

From what you've described, if you had a gas water heater for domestic, a 40 gallon with a 32k btu burner would be sufficient. If you go with a 40 gallon indirect with a 55k btu boiler, you'd have more domestic capacity than the 40 gallon gas water heater would give you.

Expansion Tank

@ March 8, 2014 5:06 PM in Pumping away ? I must have something messed up! Help

There are charts and formulas for sizing the expansion tank. The main factors are the volume of water in the system, the delta T from coldest to hottest water temp and the maximum pressure differential from cold static fill to high limit cut off. You can find the formulas on this site or online.

That being said, I can almost certainly assure you that a 20 unit facility with a 175k btu boiler and high temp emitters is gonna require far larger than an x30 tank. I would guess it would take at least a 90, but doing the math is the only way to get it right. There is no way to get things right in hydronics without doing the math properly.

And, I concur that 011 circ on the primary is way too much. The fire tube heat exchanger in the T.T. Boiler has very little head loss and does not require a large circ for that size boiler. Probably a 007 or Grundfos 15-58 would be more than enough. But, do the math and check the boiler manual for the head loss at the required gpm and follow their pump sizing charts. You probably did not need p/s piping unless the second loop off of the secondary has very different temp or flow requirements than the first loop.

Neat workmanship is nice, but proper design is the foundation everything is built upon. Even on a replacement, the job is not done right without proper design. Except for doing a heat loss calc, the other design factors would not have required more than 15 minutes time if you know the formulas and/or follow the charts in the manual.

Please, we want you to excel in this trade. So, take some time to learn the math and how to size and design things.


@ March 8, 2014 4:32 PM in 4-zone hydronic radiant heating system

A radiant floor can become air bound and can be difficult to purge if you don't have manifolds with flow setters and purge valves. Baseboard radiators can become air bound too but generally don't require as much apperatus, especially if they're looped in series like most are.

So, do you have baseboard rads or radiant floors, or both?

Not a Rad

@ March 8, 2014 4:16 PM in What is this?

It's a convector. Could be one of several brands.

Heat Emitters

@ March 6, 2014 5:28 PM in 4-zone hydronic radiant heating system

What type of emitters do you have? Baseboard, in floor, staple up, slab?

Not sensitive about the tankless, just tired of seeing people being ripped off by hacks and Internet peddlers. This topic comes up every week on here. There's a long post from last week on the "main wall" that's entitled "How Prevalent is This" that's deals with this.


@ March 6, 2014 11:04 AM in 4-zone hydronic radiant heating system

Because it's a DOMESTIC water heater, not a boiler.

It is not designed, controlled or approved for space heating and probably now has no warranty because of its mis-application. It probably won't last 3-5 years.

At the moment, I don't have the time or the inclination to go into a long dissertation on the particulars of why its wrong; I've done that in several other posts and so have others here. You can search the site and find them.

A little bit of common sense: if a tankless water heater could take the place of a boiler, there would be no need to make boilers.

The decision to use a tankless is driven by two things:
First, the amount of mis-information dissimenated mainly through Internet peddlers and hacks.
Secondly, man's nature to try a get something for nothing or less than what it's worth.

The first preys upon the second and finds more than an ample number of recipients for its wares. These folks sooner or later come to realize that the laws of physics will out-weigh the laws of economics - every time.

Oh Boy, Here We Go Again.

@ March 6, 2014 9:54 AM in 4-zone hydronic radiant heating system

That's definitely the wrong appliance for space heating. It's designed, controlled and approved for domestic water heating. It appears there's a second one to the left. Is that connected with this one?

If this unit is tied to both your domestic and space heating, you have the potential for serious health and system issues. Not the least of which is Legionella.

The piping is so convoluted that I can't follow it from the pic, but if this is an open loop, that would account for the problems youre having.

I would suggest getting a REAL hydronics pro to look at what you've got, not the hack who did this.


@ March 6, 2014 1:12 AM in Burnham recall?

Here's a link to the recall notice:
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