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Loretta
Baseboards warm even with thermosat lowered

I have 3 zoned hotwater baseboard heat.I'm mystified why two of the zones will circulate hot water when the thermostat is lowered.It dosen't always happen.But after vigilant observation it seems to happen after the hot hot water heater has been on.I don't understand.If the baseboard heat is a closed system,and the hot water is a closed system,how can one effect the other?

Pelton
Re: Baseboards warm even with thermosat lowered

Could you give us more info as to the type of zones you have----some systems have ZONE VAL VES, and others have ZONE CIRCULATORS (PUMPS)---it's common for both ZVs and ZCs to have minor problems that need adjusting.

Loretta
Re: Baseboards warm even with thermosat lowered

The system has 3 Taco Cartridge Circulators and a Taco Zone relay board.

Pelton
Re: Baseboards warm even with thermosat lowered

This post modified to reflect discussion on zone circulators.

You probably should have a service technician over the house to check the Taco Relay board to make sure it is wired correctly---if there was some recent service done on the relay board some wires could have been crossed----as you stated, each of the ZCs operate independently on a call for heat from the T-stat in the rooms, or a T-stat inside the aquastat attached to the boiler (for the HW)---has this problem cropped up recently, or has it been going on for some time?

Google "Taco Relay Board Wiring Diagram" (include the model # of the relay board); and Google "Taco Zone Circulator Wiring Diagram" to get to Taco's website to check the diagrams they have with your own setup.

Loretta
Re: Baseboards warm even with thermosat lowered

Thanks for your help. Looked for manual metal arm on the zone circulator,can't find it. It's evident I'm over my head on this one. This has been happening on and off for a few years. Techs thinks they fix it,then its back. I'm going to have to call a tech and keep at it. I appreciate your advice.

Pelton
Re: Baseboards warm even with thermosat lowered

That's MY mistake----I thought you said you have zone valves, and in fact, you have zone CIRCULATORS.

Forget the previous post about zone valves & look on older Taco circulator systems for a FLO-CONTROL VALVE just after each of the circulators (pumps) that serve each of the 3 zones----the FCV is designed to OPEN when that particular zone & circulator call for heat in order to supply hot water TO ONLY THAT ZONE, AND NO OTHERS---and remain open while the other 2 flo control valves on the other zones remain closed to prevent unwanted hot water flow thru the other 2 zones (thermosyphoning); however, often times gunk in the boiler water often gums up the free movement of the internal swing-gate mechanism and the other one or two flo control valves remain open when they shouldn't be, allowing hot water to flow thru the other zone, or all 3 zones at the same time.

For older Taco circulators, there is a separate flo-control valve, and the remedy is to manually & physically "excercise" the little thumb tab that is usually on the top outside of these valves between your index finger & thumb until you can feel that it moves freely back & forth inside the valve housing; for newer Taco zone circulators, the flo-control is integral with the pump; see the site below to replace the IFC (integrated flow control) if you have one of these new circs; the model # on the newer circs begins with "00".

http://www.taco-hvac.com/uploads/FileLibrary/102-135.pdf
http://www.taco-hvac.com/en/products/Flo-Chek/Products.html?current_category=183&view=FAQList#
http://www.taco-hvac.com/en/products/Flo-Chek/products.html?current_category=183
http://www.pexsupply.com/Bell-Gossett-Flow-Control-Valves-797000

jpsmithny
Re: Baseboards warm even with thermosat lowered

I had the same problem in my newly installed system. Turns out the "helper" forgot to install the backflow valves in the circulator pumps.

HoustonRemodeler
Re: Baseboards warm even with thermosat lowered

Back flow preventors or electric valves will help prevent the water from circulating by itself when another part of the system is on or when its setting idle.

What happens;

The warm water wants to rise. It will slowly flow past the pump and rise into the upper reaches, making the baseboards feel warm. As the water cools, it flows back down, helping the siphoning effect raise the hot water. Granted its no where near as fast as a pump, but it does work nicely.

We used this method to heat a swimming pool; We ran pipes from the pool up to the attic and back down to the pool again. In the attic we used finned baseboard heating tubes then switched back to copper. Very quickly we found we didn't need the circulator pump most days unless we wanted immediate temperature change.

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