Heating Controls

[rkinsella]

Hi all,

I had some basic thermostats fitted to my heating system last year, with 2 zones upstairs and downstairs the basic system features a "manual return" in the hot press see the picture below.

Untitled

• rkinsella
• 2 Jan 2012
• 1

The basic problem is that the zone exclusion valves never close completely, even when the thermostat closes the valve the water pressure from the pump opens it again (they are spring loaded valves).

This problem is worse downstairs than upstairs, closer to the water pump I guess. I can actually hear the valve creaking open and closed under the water pressure when its supposed to be closed .

I have a set of (relatively) new valves to be fitted and these are rated to a much higher bar. I am just nervous that when they go in they somehow break my pump as my heating zones have never really been "closed" before (the pump has always pushed them open). What are the chances?


Thanks

Ray Kinsella

 

[bhm1712]

This to me (as a none plumbing expert, although im good with controls) looks to be piped up very strangely.

Is it me, or does the return pipe from the cylinder go through the manual gate valve back into the main return pipe, as well as being routed back up the very badly bent (squashed on the bend) 15mm pipe into the flow?

The valves should not be forced open by the pump. Who fitted the cylinder stat so high up the cylinder wall?? this should be no more than 1/3 up.

There shouldnt be a high pressure in the system, 2 bar maximum when hot i would think, and any zone valve should be able to close under the pressure

 

[bhm1712]

what are the symptoms of the actual fault? are you getting hot radiators with only the HW on and vice versa?

 

[DP]

BHM, what do you find strange?

I think you need to 'look' closely as it will be evident the 15mm pipe is a bypass

Agree the stat is located incorrectly

There shouldnt be a high pressure in the system, 2 bar maximum when hot i would think, and any zone valve should be able to close under the pressure

I think the OP is talking about maximum pressure the motorised valves or perhaps the radiator valves are specified at.

OP- Look at the 15mm pipe that goes into the bottom connection tee and other end of said pipe connects to tee on the inlet to the blue valve. There is a valve on this pipe. What orientation is the slot in relation to the 15mm copper pipe run

Me thinks this valve is closed and the pump is forcing open the motorised valves. It woold be prudent to fit a bypass valve instead of a silly ballofix

 

[holty]

Is it me, or does the return pipe from the cylinder go through the manual gate valve back into the main return pipe, as well as being routed back up the very badly bent (squashed on the bend) 15mm pipe into the flow?

the 15mm would be a crude manual bypass via the service valve fitted. and the gate valve used as a balancing valve.

 

[holty]

beat me to it DP

 

[rkinsella]

Sorry lads,

I might have confused matters by putting up a picture of the hotpress upstairs when the issue is with the downstairs zone and valve. Upstairs is fine - no problem, downstairs shown below is the issue.

Untitled

• rkinsella
• 2 Jan 2012
• 1

The downstairs zone valve is literally 5 feet from the water pump, this is what me think proximity to the pump (pressure) is the problem . What happens is:-

* That the downstairs zone hits the correct temperature.
* The thermostat switches the valve off (removes power) and the spring in the valve closes the valve. (All the radiators should begin to cool)
* The water pressure in the heating system pushes the valve slightly open and some of the radiators remain hot.
* I hear a grinding sound, presumably of the valve opening and closing.

Ray K

 

[holty]

is there a directional arrow on the valve body. can't see it in on the pic but might be on the other side. check to see if the flow through the valve is the right way

 

[mysteryman]

If you are saying that the pump continues to run with all motorised valves closed, then that is wrong. There should be a bypass if there is a pump overrun circuit on the boiler. The bypass should ideally be a small radiator or heated towel rail with lockshield valves, so that residual heat is dissipated from the boiler.

The cylinder thermostat should be above the coil on a fully pumped system, as it is in your case. You need to take the temperature of the heated water toward the top of the cylinder.

 

[rkinsella]

If you are saying that the pump continues to run with all motorised valves closed, then that is wrong

This is exactly what I am saying.
You can see the bypass in the first photo, its just a small pipe.

Ray K[/quote]

 

[DeltaT2]

BHM, what do you find strange?

I think you need to 'look' closely as it will be evident the 15mm pipe is a bypass

Agree the stat is located incorrectly

There shouldnt be a high pressure in the system, 2 bar maximum when hot i would think, and any zone valve should be able to close under the pressure

I think the OP is talking about maximum pressure the motorised valves or perhaps the radiator valves are specified at.

OP- Look at the 15mm pipe that goes into the bottom connection tee and other end of said pipe connects to tee on the inlet to the blue valve. There is a valve on this pipe. What orientation is the slot in relation to the 15mm copper pipe run

Me thinks this valve is closed and the pump is forcing open the motorised valves. It woold be prudent to fit a bypass valve instead of a silly ballofix

I agree with Danny, fit a good quality bypass valve. Is it just me, but I can't ID the yellow head zone valves?? Where's the circulation pump sited?

 

[matt1e]

Is it just me, but I can't ID the yellow head zone valves??

I'd have a guess at "Sauter" delta but only as they are the only ones I know that manufacture in yellow

and I'll agree with holty regarding the possibility of the valve fitted the wrong way around

Matt

 

[holty]

indeed it is a sauter valve in the first pic. big give away is when you enlarge the picture and the valve says sauter on it these use a detachable head with a plug in lead. so if ever need changing you just plug the lead into a new head without wiring. p.s these are directional by the way.

 

[DeltaT2]

Sauter zone valves??!! 38 years in the trade & never heard of them!! Oh well as they say; you learn something new every day. Thanks mate.

 

[matt1e]

Sauter zone valves??!! 38 years in the trade & never heard of them!! Oh well as they say; you learn something new every day. Thanks mate.

they have been around a while delta
I come across their commercial/industrial proportional actuators quite often but got to admit its the first time I have seen them in a domestic setting as per the ops

Matt