Thrush Flow Control valve overheating issue

anthonymatthews

Hey everyone so I'm working on a 9 zone heating system in a 3 story apartment building and one of the apartments on the third floor is overheating due to the Thrush flow control valve that's on the supply side being stuck open causing the heat to gravitate towards this apartment even when it's not calling for heat . Its an older valve Thrush 114-A from the 50's. Id rather not mess with it right now especially with winter fast approaching. All the apartments are zoned with Grundfos circulator pumps on the return side that pump back into the main return header. Would it work if I installed a check valve that is made for the circulator pump which has to be installed on the discharge side of the pump to prevent the ghost heating issue? The inlet/suction side of the circ pump is receiving the gravity supply water then going through the circ pump out of the discharge side back into the return with the pump off. So I'd be gravity flowing into the check valve with the hope that the check valve is strong enough not to open until the pump turns on. Obviously its kind of opposite of how a check valve is designed to work, I wouldn't be pushing against it closing it id be hoping it held closed with pressure from behind it until the zone calls for heat. Any thoughts on if this might possible work? I am in the process of trying to get literature of what pressure the check valve opens at but so far I'm just waiting on a response from Grundfos, Thanks.

Big Ed_4

You sometimes have to clean flowvalve seats with find steel wool . I have not seen a Thrust in years but if it has a lever set it to the closed position like the old Taco ..

PC7060

Check the control lever / set screws on the valve. The older thrush valves can be set full closed to  open. 

Pls post a picture of the valve. Looks like it has a control lever. 

https://heatinghelp.com/assets/documents/221.pdf

EBEBRATT-Ed

Yes you can add a new FLO Ckeck (not a check valve) on the discharge side of the circulator and just leave the old Trush open I would not put a flow check on the pump suction

mattmia2

Because the circulator is on the return with the flow check in the circulator, the supply is still open, it is possible you will get 2 way convection in the supply and still get ghost flow through the supply alone.

EdTheHeaterMan

mattmia2 said:

Because the circulator is on the return with the flow check in the circulator, the supply is still open, it is possible you will get 2 way convection in the supply and still get ghost flow through the supply alone.

But it will be less than you have now with the IFC circulator. Check the pump that is there to see if all you need is to add this part. https://www.supplyhouse.com/Taco-0010-025RP-IFC-Replacement-Kit-for-Select-Taco-00-Series-Cartridge-Circulators

I know this is a Taco part number. and there are different sizes of this Internal Flow Check available. But all you need to do is to see if it fits the discharge side of the pump you have. Ask Grundfos if they have a part number that will fit the pump you have

anthonymatthews

Thanks for the replies, this Thrush valve doesn’t have that manual open/close lever that I’ve seen on other ones it only has pipe plugs so I’m not sure how to adjust or check its position,but it’s definitely wide open. Here’s a few pictures.

anthonymatthews

I plan on trying this to see if it helps the issue at all.

PC7060

If you remove the smaller of the two caps on top you should find a set screw.  Adjust screw in opens valve, backing out closes.   Be careful not to back out completely, as it will come out and a lot of water with it.  It’s normal for a little water to leak around the screw when you’re adjusting that’s the reason for the brass cap on top.

Is this a new problem or an ongoing situation for many years? Doesn’t look like that caps been removed quite some time.

Look for a patent number, you can Google it to find the detail drawings.

Worst case is you will have to drain down the system and remove large cap located on top. This will give you access to clean the flow control assembly.

WMno57

Photo of the Thrush 115 on my system.

I've never messed with it. I follow the philosophy of "if it ain't broke, don't fix it".
Both my 115 and your 114a are in the 1946 Thrush catalog here on HeatingHelp.
https://www.heatinghelp.com/systems-help-center/h-a-thrush-and-company-catalog/
H. A. Thrush is still in business in Peru, Indiana but they no longer list these flow control valves in their catalog.
https://www.thrushco.com/about-us

anthonymatthews

PC7060 said:

If you remove the smaller of the two caps on top you should find a set screw.  Adjust screw in opens valve, backing out closes.   Be careful not to back out completely, as it will come out and a lot of water with it.  It’s normal for a little water to leak around the screw when you’re adjusting that’s the reason for the brass cap on top.

Is this a new problem or an ongoing situation for many years? Doesn’t look like that caps been removed quite some time.

Look for a patent number, you can Google it to find the detail drawings.

Worst case is you will have to drain down the system and remove large cap located on top. This will give you access to clean the flow control assembly.

 Excellent thank you. Not sure how long it’s been an issue it’s a new call for me, from what I’m told at least since last year.I contacted Thrush but their of no help they tell you to call your local rep and they told me they never saw one like mine 😅

anthonymatthews

WMno57 said:

Photo of the Thrush 115 on my system. I've never messed with it. I follow the philosophy of "if it ain't broke, don't fix it". Both my 115 and your 114a are in the 1946 Thrush catalog here on HeatingHelp. https://www.heatinghelp.com/systems-help-center/h-a-thrush-and-company-catalog/ H. A. Thrush is still in business in Peru, Indiana but they no longer list these flow control valves in their catalog. https://www.thrushco.com/about-us

I agree but unfortunately the one I have isn’t working correctly. I’ll definitely see if the adjustment is set correctly maybe someone messed with it in the past and never put it back into adjustment correctly. Thrush Tech support is non existent they just say call your rep. I said I’m not trying to order parts I just want some documentation. Anyways I appreciate your guys input.

PC7060

Are there 2 of the valve in the system?

can you take a picture from further back?

anthonymatthews

PC7060 said:

Are there 2 of the valve in the system?

can you take a picture from further back?

There’s 9 of the Thrush flow valves total. The one I’m working is second to last on the supply header.

WMno57

Per the 1946 catalog a single 114a is good for 500 sq feet of radiation and has 1 1/4" connections. My 115 is good for 1000 square feet of radiation and has 1 1/2" connections. I'm using mine as an air scoop, directing air to my air over water compression tank. The apartments Thrush valves have the tank connections plugged.

anthonymatthews

WMno57 said:

Per the 1946 catalog a single 114a is good for 500 sq feet of radiation and has 1 1/4" connections. My 115 is good for 1000 square feet of radiation and has 1 1/2" connections. I'm using mine as an air scoop, directing air to my air over water compression tank. The apartments Thrush valves have the tank connections plugged.

These are also all plugged. 

Big Ed_4

Looks like tough spot to swing wrenches . I would be thinking of adding a new flow valve down stream from the old flow valve ....

anthonymatthews

Big Ed_4 said:

Looks like tough spot to swing wrenches . I would be thinking of adding a new flow valve down stream from the old flow valve ....

Very tight spot Ed. Appreciate the advice. Thank you.

Big Ed_4

Looks like cast fittings ...