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Joined on January 19, 2012

Last Post on April 15, 2014

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@ March 15, 2014 11:41 AM in smart 50 with tankless water heater

First off, The outer jacket of the smart is steel. It needs to be in the closed heating loop.
Is the alpha you have stainless? It needs to be if you are using it on the domestic side.
The alpha is idea for zoned radiant loops, it is kind of a waste to use it on the domestic side where you just need a fixed speed.
I think what you are proposing will "work"  I don't diagree with you that it is "ghetto".
I have not done on of these. Folks that have seem to have trouble with the tankless controls and the delta t.
If you post a drawing you will get more feedback.


@ March 15, 2014 10:52 AM in Confused about "pumping away" and Knight WH installation

Wouldn't the system "see" either the bipass, a zone, or the the setup you describe as resistance? Wouldn't that resistance be far greater than the boilers resistance? I don't think the circulator will know the difference. The pressure will drop on the intake side regardless.
This post brings up some interesting points.

Respectfully disagree

@ March 15, 2014 1:15 AM in Confused about "pumping away" and Knight WH installation

If this was the kbn series, I would agree with the drawing and Gordy.
The wh series firetube boiler has the headloss of a bath tub.The circulator is essentially pumping directly into the expansion tank. The bipass valve or the zones would have far more resistance than the boiler.


@ March 14, 2014 7:05 PM in The Alpha, what is auto adapt

This post covered this pretty well


@ March 14, 2014 1:47 AM in Scott's radiant heating project

You can set any mod con boiler on the market today to whatever temperature you want. In order to achieve the efficiency they are designed for you need a low return water temp and an outdoor reset curve. I would size the radiators to 130 degrees max on the design day.
What happened to the modern hydronic heating book?
This is all in there.


@ March 13, 2014 9:26 PM in Scott's radiant heating project

You can run a  condensing boiler  as low a temp as you like.
130 or lower is good target on your design day. You will want to use outdoor reset as well.‎


@ March 12, 2014 11:33 PM in Radiant Floor addition to Steam system

If your boiler has enough capacity to do the job it was designed for plus the additional load you are proposing there is nothing wrong with your idea. You will have to add up the EDR of all you radiators an apply the correct "pick up factor" for the piping losses and check that number against the boiler output rating. If you steal too much heat, the boiler will not be able to produce enough steam to satisfy the radiators.

You are correct to use a  heat exchanger. The radiant loop should be a pressurize,closed loop.

You could heat your domestic water the same way. It needs to be another separate loop with it's own heat exchanger.

Both loops would be set up so that the boiler aquastat  would fire the boiler to a lower temperature setting when there is no demand for steam.

Don't be fooled into the common thinking that you are somehow getting "free heat" because the boiler is firing anyway. A boiler that large has a great deal of jacket, flue and piping heat loss. You will be running pretty inefficiently when just the smaller loads are calling.

Dan's books on steam heating are very informative. I would recommend reading all of them before undertaking this.

It would also be a good idea to post this in the "strictly steam" section. You want to get the attention of the true steam gurus (I am not one of them).



@ March 11, 2014 8:47 AM in What is this?

I think there is a very good chance that the radiators are serviceable. Leaking fittings are common and usually repairable. Do you have pictures of the leaks?
If the radiator is not getting hot, this points to poor distribution. The problem is more likely in the mechanical room not the radiator. As pointed out earlier air in the system is a likely culprit.
Pictures of the boiler piping would help. Does the boiler have a pressure gauge? What does it read.

You have won..

@ March 10, 2014 11:34 PM in Sizing a boiler in Watertown, MA

Congratulations, you have made it.
Insist on the correct size as you have calculated and enjoy a comfortable and affordable system.
You might want to remind the gentleman that is sizing for DHW that:
The 4500 watt electric heater he installed last week puts out 15,367 btu/hrs and the 40,000 btu 70% efficient gas heater he installed yesterday puts out 28,000 btu/hrs.
Enjoy your new found knowledge.

Check valves

@ March 10, 2014 10:19 PM in Flow check.

You only need checks at the circulators with that arrangement.


@ March 10, 2014 6:20 PM in Flow check.

If I understand your description correctly, that is all you need. Post a sketch if you want to be sure.

Check valves

@ March 10, 2014 2:57 PM in Flow check.

It sounds like the circulators need check valves.The zone valves will suffice for the zones. I don't know why you would add the zone checks.

How is it piped?

@ March 10, 2014 1:57 PM in Flow check.

Unless you have very large diameter pipes, I am not sure why you need any check valves. The zone valves will prevent flow when the zone is not calling. The main circ only needs a check if it is opposed by another circ.
How is it piped?


@ March 7, 2014 1:00 AM in Heat loss through rim joist

The rim joist area is a huge area of heat loss, particularly with radiant heat.
I think 3" of well sealed foam board of spray foam is a good idea.
What type of joists do you have?
You may be able to drill new holes and move the tubes over by creating an oval.
Yoou may need to reinforce the joists.

2 Way

@ March 6, 2014 8:48 AM in New Boiler Pipings

There is nothing in your piping arrangement to force the water to bipass the heat loop and recirculate through the boiler. As you have drawn it, some water will do this but you have no real control. For a simple setup you might want to look at a boiler protection valve


2 Way

@ March 6, 2014 12:39 AM in New Boiler Pipings

How are you addressing the condensation issue with a 2 way valve?


@ March 4, 2014 11:50 PM in New Boiler Pipings

Your new drawing is not addressing the condensation issue. You have to add a bipass of some sort. A 3 way or 4 way mixing valve with an electronic controller would be a good option.You could also integrate outdoor reset with this strategy.
Do you understand why the flow directions are incorrect in your drawing? It is not because you are calling one primary and one secondary.
The pipe flow rates and btus are listed in the conversion factors tab at the top of the website.

Road to nowhere

@ March 4, 2014 11:42 AM in 4-zone hydronic radiant heating system

If the system has worked in the past there must have been reverse flow.
Yes, zone valves will allow reverse flow. It is often more noisy.
A drawing is needed.


@ March 4, 2014 11:25 AM in Perplexing radiant floor question

The manufacture should be able to tell you what the normal range specs should be for your particular mat.
The ohms need to be measured with the mat isolated from the power. The amps can be checked with an amp clamp while the system is energized.
The best practice for these installs is to check the ohm rating before and after the install and record the readings. This catches the tile guy's mistake early in the process.
Some manufactures will list the factory readings on the ends of the cables or in the literature provided.

Either way

@ March 4, 2014 8:33 AM in Wiring ALPHA 55 vs.Grundfoss 15-42

Your alpha is designed so that it is OK to leave it powered on all the time. With most systems you can just plug it in, put in "auto adapt" and leave it alone. It senses that the zone valve has opened and does it's thing.
If you prefer to turn it off and on, don't use "auto adapt" as it will reset itself every time it powers back on. If you switch it like your existing setup, it would be better to put the circulator in one of the "constant pressure" modes.
There are tons of these things installed both ways. I think it is personal preference.


@ March 2, 2014 8:12 PM in Unequal circulators in series

I assume you are referring to the fancy new name they have for Maintenance Guys?
I would think it is a bad idea. Why not evaluate the system and put in the right size circulator.


@ March 2, 2014 6:32 AM in New Home, Which heat source????

I spent a summer there as a kid. Great place!
Check out this spread sheet.
I think it is a bit easier to use.

Pellets are by far your cheapest heat source. A pellet boiler would work well for your domestic water and infloor heating needs. Solar hot water would also tie in nicely. You could design the solar to handle all your DHW needs in the summer when solar works best and to suppliment the other system in the winter.

. Another good calculator.
It is designed for PV, but will give you an idea how much sun is available in you area.

An ASHP would be better than propane or electric but not as good as pellets.
You could use a mini or multi split for AC in the summer and heat on cool spring and fall nights. The COP would actually be better than trying to run it all winter.

Is this a full time residence?
What kind of budget?

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