Circulator pump

[KeithH]

I turn up the thermostat it calls for heat the boiler kicks on but the forced hot water baseboards don't heat up now. it was working fine yesterday. Is it the circulator pump? I have a grundfos nonsubmersible circulation pump on a hydronic heating system. Any help would be beyond appreciated!

 

[ewdudley]

Is there power at the pump? Is there power leaving the aquastat? Does the pump sound like it's turning when you put a screwdriver stethoscope on it, or does it just hum, or does it make no sound at all? How soon before your pipes will freeze?

 

[KeithH]

i think the pump is working, or there is a hum anyway. The pipe leaving the pump is hot, I have 2 zones in my house this pump runs the first and second floor, my other zone on a different pump runs the basement. The baseboard is cold on all of the first floor but giving off heat in my daughters bedroom upstairs and one other heater on that floor is warm but not enough to give off heat. Why would one heater work and the rest on the zone not work? I only discovered this a few minutes ago

 

[Mike Fromme]

Frozen pipes?

 

[velvetfoot]

Frozen pipe?

 

[velvetfoot]

LOL. Great minds. How would you locate where the blockage is, other than looking for a leak.
As an aside, a local bowling alley burned because frozen pipes were being thawed with a heat gun, which you would think would be better than a torch, but still...

 

[KeithH]

I guess it's possible but idk that's why I'm here lol. All the pipes I have access too seem fine, but my basement is fully finished with a solid ceiling so I have no access to any pipe after it leaves my boiler room

 

[maple1]

If not frozen, likely an airlock. You should have means to bleed/drain your zones, if it was a decent install. On mine, each zone has a ball valve shut off right before it hits the return manifold, and a boiler drain just before that. So I just have to close the ball valve, and open the boiler drain (with a hose attached to a bucket or drain) to purge. If nothing comes out, I bump my circ up to full speed & it then purges.

But my parents had a mysterious stop of flow last year. After doing every purge trick we usually do & could think of, I finally discovered they left an outside door cracked open all night, which opens into a closet entry way, and the rad in there was frozen solid. Few minutes with a hair dryer had it flowing again. It was a very cold night, but the first time for a pipe freeze there in over 50 years.

 

[velvetfoot]

Thing is, locating it. I'm thinking get some heaters in there and safely heat up the house? It reminds me of when my VW Beetle TDI diesel gelled up in an unusual cold snap. "Tow it to a warm place" was the advice, and it worked. No pipes would break making a mess in that case though.

It's a tricky situation. You don't want the autofill valve to fill up your house in case a leak develops, and what if you turn it off? Rely on the pressure relief valve and the low level shutoff, if system is unattended at the time?

 

[mike van]

I had a Gundfoss seize up on me last year - Or it could be an air lock as maple1 said - Usually for an air lock though, you had to have had some recent work done, and it wasn't bled out?

 

[GENECOP]

Just replaced a Grunfos today....my experience has been, If you can hear the pump running, get ready to replace it...but Air is the number 1 most common problem for me.....

 

[Armaton]

Pump could be working but not at peak and just sending minimal water to loops, not enough to heat entire zone?

 

[maple1]

I don't think I'd go too long without getting a plumber with the right thawing gear in there, if you can't get things flowing. Busted pipes could really mess you up.

 

[KeithH]

I have a guy coming today. Now I have no heat in either zone. Thankfully I have a pellet stove so my wife and kids are warm. Thank you all for taking time to help me out though. I'm trying to learn how to do all this myself but this is all new to me. Thanks again!

 

[maple1]

Good luck. If you were running the pellet stove for heat with the baseboard thermostat turned down, during a cold spell, I would bet on the pipes. There is a gadget you can get that will run your zones for a bit (exercises them) once in a while, that you hook up to a thermostat. Forget what it's called but some in the pellet stove forum use them.

 

[KeithH]

My heat never turns off, and the pellet stove hasn't been strong enough to heat the house as much as we would like so I have made sure to use them both to prevent frozen pipes. I had a pipe burst last year and I have done all I can to prevent it. When i started to have the problem my heat was on and working all day, just randomly stopped.

 

[maple1]

Any updates?

 

[KeithH]

Yes a lot is going on but I'm pretty sure I had a frozen pipe, after the guy I had look at my furnace left, my baseboard heater on the first floor had heat at the beginning but only for a foot or so and then the pipe went cold. I blasted the heat overnight and we had a slight warmup the next day and all of a sudden the heat worked throughout the zone. Thank god for no broken pipes. Thanks for asking and thanks for the help everyone. I appreciate it big time

 

[Mike Fromme]

If your pellet stove is keeping the baseboard from running (and causing frozen pipes) you can add glycol to the system or wire in some sort of pump exercise circuit...

This is plug and play IF you have a newer taco sr relay controlling your zones

(broken link removed to http://www.taco-hvac.com/products/electronic_controls/pc600_series_powerport_cards/pc610_pump_exercise_plug-in_card/index.html)