Circulator Pumps vs. Zone Valves

hagferd

Contractor installed separate circulator pump for each zone as opposed to zone valves. Now we're getting heat in zones where heat is OFF and pump is not running! Is it possible that active pump is not only pushing return water back into boiler, but also reverse-cycling it through other loops?

Dana

If there are no zone valves, there is no positive shutoff for each zone so they are open to heating by convection as long as the boiler is warm. Warm water goes up, naturally by convection, cold goes down. I believe the temperature difference for this to occur is under 10 degree,s. They have to install flow checks on each zone. This is a weighted check valve that simply falls shut, since the check is heavier than water, whenever the circulator for a given zone shuts off. No more convection. I have seen and repaired many a system where the contractor mistakenly used check valves in place of flow checks. If this is the case then they must be replaced with flow checks.

hagferd

Thanks for replying.

I thought about the possibility of convection. However, when the "phantom heat" appears in the other zone, it is not just warm....it is actively radiating heat. That's why I thought the return water from the activated loop may be cycling back through the non-activated pump on the other loop.

The only othetr thing I can think of is that there is a plumbing cross-connection between the loops somewhere in the walls. I don't even want to think about that possibility.

joe_6

How many zones are there and did he install flow control valves as mentioned above.

hagferd

There are 3 zones, circulator pump for each. There is no other kind of flow control valves, check valves, etc., unless it is integral in the pumps.

Any ideas, speculation on why this is happening would be appreciated. Is my theory on this problem likely?

Dana

Even if it was pumping return water thru another zone backwards, which is possible but very unlikely, the flow check is a one way valve and would stop that as well. Are there split zones, meaning do you have the same number of supply and return lines at the boiler. Can you post a drawing or picture of the near boiler piping. Its hard too tell what may be happenning without seeing something.

Dana

See my additional questions above your last post. If you have a split zone system, which is 1 supply going out to the feeds and then 3 returns coming back, you would have to be able to access the tees on the supplies and mount the flow checks at those branch fittings. If this is the case, you may have problems.

hagferd

No split zones; 3 supply, 3 return.

One reason I think it may be a reverse cycling issue is because the RETURN piping on the affected zone (right above the pump) is hotter than the SUPPLY end of that zone (right outside the boiler)

Mark Hunt

Definately need


flow checks for each circulated zone. When any circulator runs it is pulling water through the other zones and they will heat.

Mark H

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Dana

Without seeing a drawing it sounds to me like all you should have to do is have him comeback and install the flowchecks and the problem will be gone. He might want to consider purchasing Dans books on pumping and piping available on this site. Their are several available on all types of heating systems and if you were to ask on this site I'd be willing to bet every heating contractor that comes here has them all.

hagferd

Would you recommend flow checks or zone valves?

Mark Hunt

Flow checks. NM



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hagferd

Just so I understand.....these flow checks allow water to flow only one way? If that's the case won't water in the inactive loop still get drawn through by the active loop? I'm not sure I understand th

Rich C_2

It appears that you need flo checks

> Thanks for replying.

>

> I thought about the

> possibility of convection. However, when the

> "phantom heat" appears in the other zone, it is

> not just warm....it is actively radiating heat.

> That's why I thought the return water from the

> activated loop may be cycling back through the

> non-activated pump on the other loop.

>

> The

> only othetr thing I can think of is that there is

> a plumbing cross-connection between the loops

> somewhere in the walls. I don't even want to

> think about that possibility.

Rich C_2

based upon the thread

it appears that you need flo checks on each zone. If each circ has isolation valves they can easily be replaced with circ that have integrated check valves.

hagferd

There is no isolatoin valve on any of the zones.

kevin

before the flow.....

checks are added make sure that the pumps are not flow check type... What is the make/model # of the pump? That is another easy fix if no flow checks were added(flow check pumps)I can't imagine someone for getting flow checks on the system. Maybe he asked for flow check pumps and was given the wrong on by the supply house...wouldn't be the first time that a supply house filled the order wrong..kpc

hagferd

Here is a link to the pump spec.....I can't tell from this if there is an integral flow check in the pump....

http://www.taco-hvac.com/Brochure.45/web_detail.html?Product_Group_ID=007&current_category=47