Heating of hot water also heats up 1 of the three zones

Olly

Hi all. We just bought a house with a Weil McNeil P WTGO-3 oil furnace with a tankless coil for hot water. We have three zones for heating. Everytime the water in the coil reaches the minimum set temp, the furnace starts to heat it up until the max temp is reached. So far, so good. However, during heating up of the water coil, one of the three zones also heats up. The pump however does not seem to switch on (only when that zone's thermostat is actually asking to heat up)

I was wondering whether the tankless coil system is totally seperated from the heating of the baseboards. Is there a valve in between or something that can be broken so that each time the hot water is heated up, also that same one zone heats up (without a pump pumping?)

We have an Argo Industries ARM 861 3 DP circulator relay with 3 zones (and expandable). For the hot water we have a Honeywell triple AQUAstat relay where we can set the min and max hotwater temp and a differential knob. We have been able to to some adjustments with those temperatures to at least minimise the hot water heating up time (while simultaneously the master bedroom zone gets heated up...)

Who could help us out?

meplumber

Pictures of your near boiler piping would be great.

It sounds as if you have a flow check or zone valve on that zone allowing the water to pass thru.  The flow checks are installed to prevent thermo syphoning of hot water through the zones where circulators are used.  In zone valve systems they are not always needed. 



Pics will help us narrow it down.

billtwocase

do you have

3 circulators, or zone valves? Sounds like the hotter the water gets in the boiler, the more you are getting gravity feed heat. You either have a zone valve that is open, or not seating, a flow check, or IFC not seating. Need a little more info. You are maintaining a low limit for your tankless hot water. I should be working independently from your heating zones, unless someone has tried some innovative operation. Is there a storage tank also?

icesailor

WTGO Boiler:

Two things, you probably have a flow check that is leaking by. But it should be leaking all the time and the zone would be hot all the time.

Also your ARGO controller is probably wired wrong. There should be two terminals in the Argo controller marked "ZC" and "ZR". In the Honeywell triple acting control. there are also "ZC" and "ZR" connections. If wires are not connected on these terminals, your control will not work properly.

If you have a tankless only, they probably have the operating control set too high. You need a storage tank so you can set your temperatures lower. Everyone will tell you to put in an indirect but you can install a storage tank for a lot less money and it will work just as well.

In MY opinion. 

Olly

Heating of hot water also heats up 1 of the three zones

Hi Meplumber, thanks for you incredibly fast response!

Have no pictures yet but there is one large pipe coming from the furnace that flows through 1 pressure valve towards a split in three zones. That pressure valve is on the main heating hot water pipe and regulates pressure on all three zones at once. There is only 1 manual valve per zone and immediatley after those manual valves, are the three pumps, one per zone. After that it goes immediately towards the baseboards and back to the return pipes (three; one for each zone). On each return, there is a valve to tap of the water and after that, all joins to one big return into the furnace.

Could there be a different place where a bypass valve is positioned?

I wonder also whether the furnace has just one burning mode where hot water and heating water is heated in the same go. Or is there a seperation in the furnace? 

Olly

follow up

It's three circulators that start pumping, once a zone thermostat asks for heating. I am just wondering where any other zonevalves should be as there is nothing more but per zone a manual shut off valve. Is there something in the circulators that should keep the water from flowing up to the baseboards? I would expect that only when the circulator starts pumping, the hot water would go up. It is funny that it is just one zone that has the problem while the others are also exposed to the main heating water.

Olly

follow up

Hi ice sailor. Where would the flowcheck be located? The main heating water goes to all zones at once, there is nothing but individual circulators and manual shut off valves in between. Why is it just that one zone?

Indeed we found out that there was wiring missing. There was a jumper on ZC to ZR. We removed the jumper and connected the ZC and ZR to the corresponding ZC and ZR in the Honeywell. Started up again. Lights in the circulator relay respond properly as described. Thought we solved it but then it turned out to make no difference as the same zone got heated again:-(

Ironman

Flow Check

See the attachment concerning what a flow check looks like and does. You should have one on each zone or else have an internal check in each pump.



What make/model are your pumps? Some pics would help.

icesailor

Zone Flow Checks:

If your system is fairly new, you may have circulators with internal check valves. If so, you may have debris in a check. If they are green Taco circulators, is there something on the wiring cover like "007 IFC"? IFC stands for Internal Flow Check. I personally consider them another bad new idea. I am sure that sooner or later, one will bite me in the butt when I drain and winterize a house with them in the circulators and I have no way of knowing if they are in the system nor if the system drained back to the boiler. If it doesn't drain back, it will be a bad split in the main. The engineers that design this stuff never asked anyone that has to service this stuff what WE think.

Olly

follow up

Hi Ironman, thanks for the information. This afternoon I go back to the house, take some pictures and write down some types/nrs I can find to post.

to be continued...

Olly

follow up

I expect it's max 12 years but I also know there has been some frozen pipes this winter. It might be newer.

Tonight I go back and get some pictures/info.

thx!

Olly

pictures

Hi All,

I think I have found the flow control valves and indeed the one from the heated zone was not completely closed. I have included some pictures. I have closed it and hopefully it is working now. A short test was promising.

To you all, thanks a lot guys for helping me out here!!!!

all the best!

Olly

icesailor

Flow Checks:

That picture of that green, rusty thing is a flow check. You said that one wasn't fully screwed down. After you screwed the bonnet down, did the circulation stop?

icesailor

More Flow Checks:

Those green things above the circulators are the flow checks. You can stop the flow by closing one of the valves below the circulators. Close the valve of the zone that is not working properly. Any possibility that those new Grundfoss circulators have IFC;s in them? That would be interesting, two flow checks.