Radiant heat loop not working!!

GroundUp

You have now repiped it to be more wrong than it was before. The flow was correct, as the arrows on the valve body indicate. Most 3 way thermostatic valves have the mixed on the bottom, but yours has the mixed on the left and cold inlet on the bottom- per the arrow. Flow before was accurate, but the pump was on the wrong side of the valve. The inlet of the circ needs to be on the mixed outlet port of the mixing valve in order for that part to function properly.

Zman

psb75

Ralphxyz,
Really... STOP what you are doing. Take a deep breath. You have re-piped the mixing valve WRONG. You are pushing water AGAINST the mixing port on the tempering valve. The circulator needs to PULL through the mixing valve.
If you want good help, you need to HELP the folks on this forum understand your system. Your photo's are "not so helpful." Folks on the forum need to see your WHOLE system--not random parts of it. Try to draw out a schematic and post it here. MUCH can be resolved this way. An intelligent discussion will ensue.

Ralphxyz

Zman, thanks, gee a clear picture really helps, so the circulator goes on the mixed side pushing it through the loop pulling it through the tempering valve.

I have it pulling through the loop.

I have not looked at a hydronic heating systems in a lot of years but I seem to remember the circulator(s) pulling through the loop.
There usually is a manifold on the return side of the boiler.

My house circulator (installed at the factory) is pulling through the house loop.

With the original piping to the tempering valve, which now appears to have been correct, and the circulator pulling through the loop it did not work.

Now, with the circulator working, if I close and open the tempering valve, manually, it works. When I move the bulb on the tempering valve all the way to the left and then all the way to the right I hear the water moving through the valve and the mixed
supply heats up. If I do not manually do this the loop only heats up when the house circulator is running. (At least that is my current thought)

This radiant loop was added at least 10 years ago and I used to
just leave the circulator running 24 hours a day for 6 months of the year so there are thousands of working hours on the loop.
Of course there wasn't any flow it did not work, only when the house circulator was working was there actual flow through the loop. I replaced the circulator with one (used) from ebay.

I am tempted to keep the existing piping and replace the tempering valve, it is at least 10 years old.

Thanks again, I am working on a sketch.

Ralph

Zman

It really isn't a "push or pull" conversation (although you are pumping into the expansion tank which is not correct).

When the circulator is outside the mixing loop, the flow though the loop is not constant, it varies depending on the position of the mixing valve. The only reason it "works" (temporarily) when you adjust the valve is that you are opening the valve allowing flow. Your system will never work correctly unless you move the circulator.

Ralphxyz

Thanks Zman, sloooooowly it is sinking in. I am/was Gooling radiant heat and I see what you are saying about the position of the circulator.
When I am moving the circulator I should restore the piping to the Tempering valve also?

Zman

Yes, put the piping back where it was.

Ralphxyz

Thanks again Zman!

Different subject this should be a new thread.

I remember at least 60 years ago my Father telling me:
"a circulator is not a pump" but he never really explained what a circulator was or how it worked.

I always wondered what it would look like with some gages.

Well 60 years later here ya go:
Boiler Pressure: no circulator working just static pressure:


Static pressure at circulator:


Inlet: Circulator running

Outlet: Circulator running


While there is a reduced pressure on the inlet there is no "pumped" increase in pressure on the outlet side.
A circulator is not a pump.

Thanks everyone this has really been informative and helpful!!

Ralph

Tom_133

Ralph,

Im glad you stuck with it, hope it works out well.

ChrisJ

Your father's point was it's not really lifting water because the drop is the same as the lift. It just circulates it.


But it's still a pump.

He was right but I think you missed the point.

Ralphxyz

Damm, pay attention stupid.

Inlet Circulator running:

Zman

On this Forum they are generally referred to as circulators. I know plenty of people including engineers who use the term interchangeably. It is just not that big a deal. Except, of course to your Dad and a few other people.

Ralphxyz

A pump adds to the head, while the inlet side has lower pressure the outlet is the same as the boiler pressure so it is not "pumping" it is just circulating.

STEVEusaPA

Circulator moves water by pressure differential. It won’t add to the head if it’s pumping into the expansion tank.
https://youtu.be/tZRuqiQkukE

GroundUp

You're not really in a position to be calling someone else stupid. A circulator PUMP works by creating a pressure differential- if your outlet pressure is not higher than static, your gauge(s) is/are broken.

HomerJSmith

Circulator / Pump, to a technocrat they are different. A "pump" is speaking idiomatically and is perfectly acceptable in that regard.

I'm not analyzing this in detail, but I might suggest, if this system was properly working at one time, that the black circulator, which appears to be a Taco may have a bound cartridge. Sorry, I'm tired.

Ralphxyz

Why would you bring up the black circulator it is working fine, that is the house circulator and yes it is a Taco.

I was calling myself stupid for not previewing the post and seeing I had the wrong picture for the inlet.

The gages are brand new, there is a differential inlet is about 7#
the outlet is about 16.5 the boiler pressure is about 16. it is as SteveusaPA said
"It won’t add to the head if it’s pumping into the expansion tank."

Somehow calling it a Taco, Grundfos, B&G (are they still around)
Pump just doesn't sound right.

Ralph, and Thanks Again for all of the input.

Zman

HomerJSmith said:

Circulator / Pump, to a technocrat they are different. A "pump" is speaking idiomatically and is perfectly acceptable in that regard.

I'm not analyzing this in detail, but I might suggest, if this system was properly working at one time, that the black circulator, which appears to be a Taco may have a bound cartridge. Sorry, I'm tired.

It never worked correctly.

Ralphxyz

IT WORKS NOW

Thank you Thank you thank you everyone for your help.

Once I add some flow arrows I'll post pictures to show the new "correct" piping.

This was really wearing on me.

Now I might need to actually pay attention to what the mixing valve is doing.

The Garden Room is 16 x 20 3" cement set tile with partial insulation over a 12" dead air space this is around 10 years old so there isn't any moisture in the cement so I do not need to think about that. I bought a programmable thermostat which I need to install.

Zman

Thanks for the update. Sometimes the toughest thing to do is to take 10 steps back and question your own assumptions.
Nice work!

Ralphxyz

I wish I had a new radiant job to do, but it is not likely, but who knows, someday someone might just ask for my help.

I was so pleased when the thermostat called for heat, the circulator kicked on and the supply pipe got hot, exactly as it was supposed to. Thank you for the help.

Ralph

DZoro

Thanks to @Zman for sticking with this, you deserve the "Zman of the year award" IMO

BTW Ralph, don't use a programmable stat on your newly working radiant. Set it and forget it.
D

Ralphxyz

re: don't use a programmable thermostat

I like having the setback especially at night, would you just pick a temp out of the air until you found something that you could live with?

Probable should be a new thread.