Problem with Monoflo System

Neil_5

I recently converted from oil to gas, hot water monoflo system. I have convectors throughout the house and 3 baseboard heaters (recently purchase the home). After we fire the system up all the convectors heated up, however the 3 baseboards didnt and there is no where to bleed them. Do I have to add bleeders to the 3 baseboards? I also raised the
boiler temperature from 175 to 185 and noticed two of the 3 baseboards heated up. Is there anything I can do or my best course of action in to install bleeders on the baseboards? Boiler pressure is at 15 PSI, this is a split level ranch and the 3 baseboards are on the 3rd floor.

I have noticed that 2 of the 3 baseboards are now running
ok (hot) but the third unit in the bathroom is still cold. All the remaining convectors are nice and hot and the system is running great.

The system is Burnham Series 2 gas system, converted from oil and I noticed the pump is on the return side. Would I be able to convince my installer to move the pump on the supply side? Doubt it.

Would the bleeder valve on the baseboard fix my problem?
Just found this site, great folks and great information!

Thanks,
Neil

Uni R

Problem with Monoflo System after Conversion

What was the pressure before the changeout? If there isn't enough water and pressure in your system and you had bleeder valves up there, they would actually let air in and not out depending on the height.

Neil_5

Wasn't paying much attention before conversion, I kinda got more involve durning and after the conversion. I have increased the pressure from 12 to 25 PSI but still can't get that one baseboard to fire up.

Neil

Uni R

Well...

If the rad is a high point that is fed from a monoflo branch, then it needs a vent for the circuit. Are you 100% there isn't one? It may be hidden or have been overlooked. I can't see it not having one already.

Neil_5

yea ...

I looked everywhere, the one cold baseboard is at the hight point with another one (which is now hot). The house is 1955 house with all convectors and about 10 yrs ago the kitchen, master bath and main bath were all updated. They are now outfitted with baseboard heaters and no bleeders. I checked everywhere as well as the heating guy. Two of the baseboard I can acesss from the bottom and see where they are connected to the monofo main and still no sign of bleeders. And of course the one that is cold I have no access at the bottom

Monday the installer is comming back to install bleeders on the 3 baseboards. My guess is when they converted the 3 baseboards and fire the system up all was well (maybe because the pump was on the supply?) and they never had to drain the system again.

On a separate question, I have the water temp @ 185-187 now, should I lower it to say 160? for savings?

Thanks again,
Neil

Uni R

Depends...

Ask your installer about an outdoor reset. A totally mechanical white-rogers outdoor reset is extremely reliable and far cheaper than a Tekmar.

http://www.white-rodgers.com/contractor/ptech/hydronic/info_list_hydronic.htm#1050-1

See the 1050-1 at the bottom. This would do your resets for you.

I would try 160 and leave it there unless/until you get cold and then add 5 degrees each time until you are comfortable. Your system will cycle more, but it will also be far more comfortable.

Ron Schroeder_2

You might try to LOWER the boiler pressure to only 10 psi, run the pump for a couple of minutes and then raise the pressure back up. Sometimes that will clear an air bound system.

Neil_5

Lower PSI

Am I correct to say in order to lower the boiler pressure, I can open a bleeder? Or I have to do some by the drain?

Ron Schroeder_2

You would need to close the automatic fill and open a drain while watching the boiler temperature/pressure gauge. You would want to lower the pressure to get a reading slightly above the height from the gauge to the highest radiator/baseboard.