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Hot water baseboard furnace zones acting strangely

We have a hot water baseboard heater with 5 zones from 1994ish that recently started acting weird.

About 3 months ago, I noticed that the expansion tank was leaking at the seam...so I replaced it with new. For about 3 weeks, the system was very loud, even after purging as much air as I possibly could out of it. Eventually, all the air purged through the auto fill valve and the noise is gone.

Recently, the master bedroom zone temperature wasn't varying at all as it should with our programable thermostats. At night, the temperature is about 70 at 10pm, and rises to between 72 and 77 by 6am...then drops back to 70 during the day. We have it set to 58 during the day, 68 between 6 and 10, and 65 overnight. So I turned the thermostat off, but the same behavior exists. The baseboard is always warm to the touch.

The other zones were fine, until a few weeks ago. The dining room zone will not move off of 70, even though we have a similar heating patern programmed into the thermostat. I turned off the thermostat and the temperature dropped like you'd expect it to. Turn it back on and we're right back to 70 again.

Anyone have any ideas as to what might be happening? Our heating bills are nearly $400 a month now and I assume that the heating issue has something to do with it.


Re: Hot water baseboard furnace zones acting strangely

Could you advise if you have electrically operated zone valves or circulator zone valves.

Also the make and model number of the zone valve/circulator.

Also, the make & model of the T-stats being used.

The Master Bedroom zone sounds like it's stuck open and is providing what's called "ghost flow" thru the zone.

First check & make sure the problem zone valves are not in "manual" mode; there is a little metal lever at the base of most ZV's that allow them to be manually opened.

If the MBR zone is an elec. zone valve, the end switch may not be closing as it should at the end of the cycle.

This would allow hot water to keep on flowing thru the MBR zone when any of the other zones call for heat.

If you have circulators, the Flow Check valve on the MBR zone near the circ is probably stuck open.

This would also cause "ghost flow" since the MBR zone would remain open when any of the other zones call for heat.

The Dining Room zone sounds like a T-stat mismatch problem.

Some electric zone valves are not compatible with some programmable T-stats; in other cases you have to adjust the heat anticipator inside the T-stat to correspond with the amperage draw rating in the zone valve.

Please post back.

Re: Hot water baseboard furnace zones acting strangely

Thanks for the quick reply.

It's a Burnham furnace. Current pressure is 20PSI, current temperature is a hair under 170.

All 5 zones are Taco Cartridge Circs, Model 007-F4

The controls are Argo ARM842 (3 zone) with 2 expansion zone controls, also Argo of course.

Bedroom thermostat is a Ritetemp 8022C.
Dining room tstat is a Honeywell RTH230B.

Here's a picture of the setup...sorry it sucks...took it with my phone this morning.

I know we have some corrosion issues around one zone and the air scoop...no signs of leaking yet...hoping to get another year out of it before I replace that stuff.

Re: Hot water baseboard furnace zones acting strangely


Try to find the flow-check valve on the MBR zone & twist the top tab on the valve several times to see if you can get it to move by itself; there is probably a speck of crud holding it open.

The flo-chek is located immediately downstream of the zone circulator & has a little tab on top.

Clockwise closes the valve, counter- clockwise opens the valve.

The valve has to close by itself when the MBR circulator stops pumping so no hot water can creep in from the other zones.

On the Dining room zone, check any literature you have on installing & operating the ARM842 panel.

If you have none, their installation & operation manual (pdf) is listed at the site below.

Scroll down until you find your panel.

Check for any loose wiring & tight lug nuts & any info in the I & O that pertains to attaching the Honeywell RTH230b.

Also Google Argo AR842, as well as ARM842 for more sites.


Re: Hot water baseboard furnace zones acting strangely

I had some trouble loosening all but one screw on the flow check valves as they wouldn't budge. Not sure if they should be left open or screwed tight? One is open, the others are closed or mostly closed.

I'm not sure if it's an issue, but the circ pumps pull, not push.

I have created a line diagram of the system you can see here: http://www.advantechcny.com/diag.pdf

Arrows indicate direction of flow.

Thanks for your help so far. I'll shut off the...uhh...shut off...for the zone above the pump tonight and see what happens overnight. NO heat should mean an issue with the flow control then.

Also...the Argo looks to be wired just fine...no loose or corroded wires...and the tstat seems to be wired fine too. So I'm still a little stumped by the dining room zone.

Re: Hot water baseboard furnace zones acting strangely


Wow, what a nice chart.

I suppose it IS a pov depending on the side of the circ you're standing: but you clearly have the water flow circulation direction mapped out in the chart.

Yes, the force of the pumped water sets up a directional current that does PUSH the little cap inside the flo-chek valve open (hopefully) when the circ is operating.
Then, when the circ in that zone stops, the little cap clanks down (hopefully) to prevent the pumped water from the other zones from creeping in.

Try some WD-40 or Liquid Wrench on the the little tab on top of any sticking flo-cheks.

Also GENTLY tap the flo-chek housing several times at different spots with a rubber mallet to see if you can loosen any crud particles that may be sticking things inside.

In a quiet basement, you should be able to hear the slight clunk sound when you turn the tab screw first counterclockwise to open, then clockwise to close the valve.

The valve has to remain in the CLOSED position; the circulating water will open it (hopefully), & the valve will close by itself by gravity (hopefully) when the circulation stops in that zone.

These flo-cheks have an OPEN position (counterclockwise) in the event that the circ in that zone fails; the homeowner can manually prop the flo-chek open so that heat from the activity of the other zones will provide some heat to the dead zone until the circ can be replaced.

Bell Gossett has a nice tutorial on flo-cheks with some nice flow diagrams; they also in some cases recommend a 2nd flo-chek in the return line in some circumstances.

Click onto "Homeowners" at the site, scroll down & click onto "valves", then onto Flo-control valves", then onto "tutorial".

Do you happen to have hard water in your area?

If the above remedies don't work, the zone can be shut down, the water drained & the top of the screw-on housing for the flo-chek removed so the valve can be cleaned.

I'm also still stumped on the DRZ; I suspect it might be a heat anticipator setting in the T-stat, but it's just a guess.

Please check any literature you may have on the T-stat amperage ratings, and heat anticipator settings; some of it may be online.

Could you try switching T-stats with one of the other working zones to see if that makes a difference?

Be very careful to label the wiring if you try this.

I'll scout around to try & find some troubleshooting literature in the meantime.



Re: Hot water baseboard furnace zones acting strangely


A lot of the troubleshooting sites are talking about problems with the Honeywell RTH230b and some model gas valves.

I can't make out from your photo if you are gas-fired or oil-fired.

This might apply if your Burnham boiler (you have a boiler, not a furnace) is gas-fired.

If you're oil-fired you have an aquastat which takes the 24v from the T-stat/control panel & turns on & turns off the burner/circulator.

If you have gas, the Rogers 36co3 and HP gas valves are mentioned as not compatible with the RTH230b.

Honeywell has an online installation & user guide (in english/french/spanish) at the site below; enter "RTH230b" into the advanced search box at the bottom right of the site & hit enter.
I couldn't get the pdf file to load onto my system.


One of the sites lists a Honeywell Support 800 number:


Apparently a lot of people have been calling in to Honeywell, so their experts are well aware of the various problems with the RTH230b.

Could you post back with the name & model of the gas valve, if applicable.

This should be listed in the Burnham installation manual if it can't be read from the gas valve itself.

Any wiring diagram you can post of the DR zone from the T-stat to the
boiler would be appreciated.

There's also been a lot of problems with the 5-wire color-coded wiring hookups.

Avoid forcing the tabs atop the flo-check valves too much; if there's any stem corrosion, you could end up snapping the tab/lever off & causing a leak.

Re: Hot water baseboard furnace zones acting strangely

It is a gas fired boiler. I won't be able to get the model number off the valve until friday night.

The thermostat is only 2 wire...I figured it'd be pretty hard to screw that up. DR Tstat goes to the zone tstat connection on the Argo. Straight shot, no funky hookups. No priority switch/circ on the Argo. Priority zone goes to the burner control in the boiler.

I do remember that the burner controls are Honeywell.

I loosened up the valve on the flo-checks just fine. An open end wrench to hold on to the collar and a pair of pliers losened it up easily. It was was too dificult to finger loosen.

Since I loosened up the flo-checks, I believe the bedroom zone is back to normal now. No more ghost heating overnight. Turned the thermostat back on...and we'll if it adjusts properly over the next few days.

Thanks for your help...you're awesome.

Re: Hot water baseboard furnace zones acting strangely

definatly sounds like a stuck open check valve on the suspect zone, that zone will heat some even if its circulator isnt running without its check valve closing all the way.


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