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Joined on September 1, 2010

Last Post on August 14, 2014

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Base Board Water Temp

@ August 14, 2014 6:29 PM in Is 100k BTU the right size of boiler (or HTP heater) for both baseboard heating and indirect DHW

At 160* supply water temp, your B.B.s will have their output reduced to about 75% of their rated capacity. Right now, you're getting about 38.5k btu's with 170* AVERAGE water temp (180* supply, 160* return). 75% of that would be 28.8k btu's at 150* AVERAGE water temp (160* in, 140* out).

That may not be quite enough, based upon your load calc, on very cold nights. Particularly in some rooms if the BB are looped in series. The end rooms may suffer.

Control Panels

@ August 11, 2014 5:56 PM in zone valves and Circulator

Look up Taco SR504 pump panel or ZVC 404 zone valve panel.

The SR504 controls circulators; the ZVC controls zone valves.

Circa or ZVs

@ August 9, 2014 11:47 PM in zone valves and Circulator

It really depends on the flow requirements of each zone. I generally prefer circ's over ZVs and the price is about the same if a panel is used with each (recommended for ZVs, required with circ's).

If a ECM circ is used, then ZVs would be used with it. The indirect is almost always better served by having its own circ properly sized for it.

It doesn't matter if it's gate valves or ball valves, unless the "screw" valve you're referring to is a globe valve being used to throttle the flow.

Circ Placement

@ August 8, 2014 10:54 PM in zone valves and Circulator

The proper place for the circ is on the supply line, after the air separator IF the expansion tank connects to the air separator. The place where the expansion tank connects to the system (Point of No Pressure Change) is what determines where the circ should be placed. The circ should be place immediately down stream of the PONPC pumping away from it, not towards it.

For many years, the circ came attached to the return of boilers because it could be crated and shipped easier like that. The shipping department made that decision, not the engineering department - they knew better. That lead to a whole generation of "techs" thinking it belonged on the return. The misconception is still very prevalent.

The reason for this is that if the circ is pumping away its pressure differential is ADDED to the static fill pressure of the system. If it is pumping towards the PONPC, the circ's pressure differential is DEDUCTED from the static fill pressure of the system.

What this means in practical terms is that if the circ is pumping away as it should, there will always be positive pressure at the highest point of the system if all else is right. If it's pumping towards the PONPC, then then highest point of the system may have low or negative pressure when the circ is running. The can cause air problems, cavitation and other issues.

Get Dan's book "Pumping Away" for a thorough explanation.

Bad Info

@ August 8, 2014 10:19 AM in problems with Mitsubishi split system

Your tech has given you some bad info about the ability of the mini splits to dehumidify. They do an excellent job of dehumidifying - much better than ducted split systems. They are probably as good, maybe better, than high velocity (Unico, Spacepak) because of their ability to modulate.

I agree with Harvey and Spence that dirty evaporators and/or low charge are your two most likely issues.

Regarding charging your system: the ONLY proper method is to weigh in the TOTAL system charge. Harvey's spot on when he said the refrigerant charge should have been removed, the flare redone, the system leak tested, evacuated, the TOTAL system charge properly calculated and weighed in. That is the only correct method for charging a multi zone branch box system.

This ain't your grandpa's air conditioner. Things that are acceptable on a single stage ducted system may be totally wrong on this one.

One other note: setting the cooling to 59* inside is way below the system's design. It should not be set below 68* even though the control will allow it to go lower.

Penny Wise and Pound Foolish

@ August 7, 2014 11:08 AM in Can I use a 2.5 ton coil with a 1.5 ton condenser?

Without being technical for a moment, let's look at the situation rationally. You client wants to use a piece of equipment with an installed system that it's not matched with and is insufficient to carry the load because he already has this unit. Is that reasonable and rational? I think the answer is obvious.

I have a Ram dually and my wife has a Honda. If the dually had a flat tire, would it be reasonable to try and adapt the spare tire of the Honda to the dually because I had it and didn't want to spend the money for the correct tire?

There are several good technical reasons that have been posted which tell you this is a situation to avoid. Let me add two more:

1. What refrigerant is the coil rated for? What refrigerant is the condensing unit? If it's an 8 - 10 seer coil, then it's R22. Is the C/U a dry R22 unit? If not, then you need go no further; they don't match.

2. If the coil is an ARI match, then the piston should be changed to match the O.D. unit. But you'll only have a 1.5 ton system where a 2.5 ton is needed to meet the load.

You will do yourself, your customer and the trade a great favor by putting a correctly matched system in rather than trying to cob something together because he THINKS what is proposed will save him $$.

The laws of physics will out weigh the laws of economics - every time.


@ August 5, 2014 5:34 PM in Radiant Manifold

I've got a job with those that was done by others and they're branded Honeywell. If they have motorized actuators, you can replace them with Rehau's thermally actuated ones, but they must be mounted upright.


@ August 5, 2014 5:12 PM in Brazing without nitrogen?!

For some reason that I can't remember, the dies wouldn't fit the Rigid that I had. It was the model that clicks when the flare is made.

However, I'm sure if they come with the tool, it will work great. I do every flare (gas, oil, refrigerant) that way.

It's kinda of interesting: I've brought this up in every mini split training class that I've been to. After listening to an instructor lecture for about 20 to 30 minutes on the importance of using a 410a flare tool, I'll ask them about double flaring and explain that I've been doing it for years and NEVER had a leak. I then ask them if they consider it an acceptable method. The response is usually the the same: they will confirm it with their engineers and get back to me right away. I've been waiting on Fujitsu to get back with me for over eight years now. Others said it was fine. One had no idea what I was talking about and I actually had to get the tool from my truck and demonstrate it for him. :)

Flare tool

@ August 4, 2014 11:14 PM in Brazing without nitrogen?!

Mine is Imperial Eastman, but the double flare dies didn't come with that tool - they were optional. I got them from Harbor Freight with a $10.00 Chinese tool. :) I threw the tool away and kept the dies since they were what I wanted. They are identical to those that come with the good flare tools.

Double Flare

@ August 4, 2014 6:42 PM in Brazing without nitrogen?!

The tube is essentially hemmed over and the inner portion acts somewhat like a metal gasket allowing a small cushioning effect.

Brazing on Mini Splits

@ August 2, 2014 10:49 PM in Brazing without nitrogen?!

Not all manufacturers require flares on their mini splits. Did a training class on ECR minis a few weeks ago and they said brazing was okay as long as nitrogen was used.

Did an LG 8 zone that someone else had started and all the separation wyes were brazed as that is what LG supplied with the units.

Regarding flaring on mini splits: the thicker forged flare nuts that are supplied with the unit should be used. They are the only ones approved for 410a. Also, a flare torque wrench should be used in tightening. I double flare everything and have not had a leak on anything in 15+ years of doing it.

Danfos TXV

@ August 2, 2014 1:40 PM in major problems with new carrier system

I just had to replace a Danfos TXV on a 3 ton, 16 seer Maytag that we installed six weeks ago. Could it be a bad batch of Danfos TXVs?

Separate Circulator

@ July 31, 2014 9:57 AM in Advice on adding zones

Why not add a separate cic to create the additional zone? Of course, you'll need a check valve on each one to prevent backflow between zones. The simplest approach would be to put a Grundfos ups58-58fc on each zone rather than piping in a flow check on the existing zone. I'd try setting the main zone to medium speed and the new one to low for starters and measure the Delta T on each. Like HR said, a load calc is the only way to calculate what flow characteristics are needed.

A word of caution: creating a small zone may cause the boiler to short cycle which will greatly shorten its life. If it's already condensing - and it probably is - then you would do well to heed Rob's advice. The thing that you have in your favor is the high thermal mass of the boiler and water in the system help prevent short cycling. Creating one small zone will work against that and could cause increased condensation. If the boiler won't run for a minimum of ten minutes on the small zone under normal conditions, then more buffer should be added.


@ July 30, 2014 12:34 PM in Brazing without nitrogen?!

Nice video; and it makes the point of the need for using N2. I'm not disputing that, but please look at everything I said.

I've worked on everything from 1000 ton centrifugals down to household refrigerators. I've seen a four inch suction line on a recip so full of carbon from a burnout that it filled 2 quart jars. What could not be removed by hand cleaning had to be left in for the driers to catch. They did just that and after the second change, remained clean.

I've seen centrifugal burn outs so bad that after chemical cleaning, the driers still required multiple changes. But they did their job and the compressor ran fine for many years thereafter. Don't discount what the drier can do.

A Slight Compromise

@ July 30, 2014 11:58 AM in Brazing without nitrogen?!

I almost hate that word, but some circumstances warrant it.

If it's a mini split system or multiple joints, then N2 should always be used. If it's just connecting the line set on each end (2 joints) with a properly sized filter/drier installed, then I don't see where there's enough oxidation produced to make a difference.

Just MHO, but in 40+ years, I don't know of a compressor failure that I've had in less than 10 years of service from a unit. Electrical and other component failures which would cause a compressor failure being excepted. It may even be closer to 15 years. I'm very meticulous and a leak free system, a good vacuum and proper charging are more important than a MINOR amount of oxidation.

Again, JMHO.

Primary Loop

@ July 22, 2014 7:21 PM in Suggestions wanted

I would connect the house piping to form a primary loop and then use two sets of closely spaced Tees to inject into it. Moving from return to supply, the first set would be from the indirect that's connected to the wood boiler. The second set would be from the oil boiler into the loop. This way the wood boiler would supply whatever heat it could and then the oil boiler would kick in if the wood boiler is not producing enough. You could use a strap on aquastat or ETC to hold the oil burner off if the wood is producing enough heat.

I concur with HR that some form of thermal protection for the oil boiler would be prudent.

Obviously, your biggest obstacle is your thick-skulled customer who won't listen to his pro. Setback on a gravity system is totally counter-productive. It's using more fuel and also sacrificing comfort. Not to mention the thermal stress it's imposing on the boiler.

Another issue with ODWBs is that most are slow to recover, especially when hit with a dump load like your facing when that system comes out of setback. The more buffer that you can add to the wood boiler, the better it will handle the dump load and the more efficient it will burn.

I like Harvey's solution best. :)

Still Gravity?

@ July 22, 2014 11:31 AM in How to loop 2 cast iron rads

I agree with Ice that it probably won't work well, particularly if it's still gravity. If it's been converted to forced flow, you make it workable by adding a small circ on that riser, but the first rad will still heat up first.


@ May 1, 2014 12:06 AM in Please take this survey

But SlantFin is only listed in one place. I haven't installed any of their newer stuff, but it looks like they have a good product line. Especially with their fire tube mod/con.

Argo Priority

@ April 16, 2014 11:45 PM in Buderus GB142/30 no heat as outdoor temps rise

"The main Argo is on PRIORITY for zone one". This setup will NOT work correctly when using the AM10 with outdoor reset. The water temp being supplied to the indirect will always be tempered by the reset curve.

For priority, the indirect must be piped from the domestic charging connections provided on the boiler manifold and the Buderus sensor that came with the boiler must be used in the indirect's temp well. The sensor connects to the "FW" terminals on the boiler and the domestic charging pump connects to the "PS" terminals. The boiler control will automatically provide domestic priority and override the WWSD for domestic charging. Use the dial with the faucet icon to set the tank temp.

And ditto on properly setting the WWSD.


@ April 11, 2014 9:50 PM in Can a Circulator Pump Past a Stopped Downstream Pump?

The impeller in the down stream circ will cause some resistance to flow, but like Charlie said, it won't stop it.

4 inch flex - never

@ April 7, 2014 10:08 AM in New install Furnace

A 4inch flex line will carry about 40 cfm at normal static pressure. That's 240 cfm for 6 of them - well below the minimum cfm that even the smallest (40k btu) furnace would require.

We never use 4" flex on duct system except maybe a short run to a 3x5' half bath with no exterior exposure.

4" flex is for bath exhaust fans.


@ March 30, 2014 10:19 PM in Gas piping

Any word back from Navien?

We know they monitor this site. Why don't they reply?
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