Can anyone tell me why I would have two HW valves fitted in series to my system? I was having a problem with the pump running intermittently and for no apparent reason after the system had satisfied its heat demands (not overrun, we are talking of an hour or more). The pump would run on occasionally even after the system had switched off completely. Things came to a head the other day when it came on and would not go off. I eventually traced the fault to a second H/W actuator valve fitted adjacent to the hot water tank. The motor had burnt out and as the water heated up it appeared to make the contacts close and cause the pump to run. I removed the head and the system has worked fine ever since. But why would this second valve have been installed in the first place? The actuator that is U/S is a SUNVIC SZ2301F. The other two are standard Honeywell. Do I need to replace the SUNVIC as everything appears to be running OK (apart from the expansion vessel problem!)
Two Hot Water Actuator Valves?
- Thread starter IanDB
- Start date
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Do you have an unvented cylinder? I think the Telford Tornado cylinders use an arrangement similar to the one you describe, not sure though as I don't have unvented certification. Off hand I can't remember why there is a second valve as I've only seen one such system. BTW, if it is unvented don't even consider touching it, not only are you putting yourself at risk but your neighbours too!
Yes, it's a pressurised water system - can't for the life of me remember the make of tank. The hot water tank and boiler are adjacent to each other in separate cupboards in my kitchen. The valves are separated by about 2ft of pipe hence my question about the purpose of the second one.
They were wired in parallel in an apology of a junction unit when the system was installed. Excuse me getting emotional about it but ever since day one I've had problems which have been purely down to the "plumber" and electrician who installed it in my new house (now 6 years old). It was never commissioned properly and was left with the SUNVIC valve in the "flush" position - took me a little while to work out why the pump was on continuously! The radiators weren't balanced and no inhibitor had been added to the system. After a visit from the Vokera agent at least the boiler worked properly. The state of it all did not inspire confidence in me and I wondered whether they'd fitted two valves by mistake or just to confuse me. I'm an electrical/electronics engineer by trade so I understand the sparky bits. If it's anything else I'll have a look but I'm quite happy to get someone who actually knows better to sort it out. End of rant!
They were wired in parallel in an apology of a junction unit when the system was installed. Excuse me getting emotional about it but ever since day one I've had problems which have been purely down to the "plumber" and electrician who installed it in my new house (now 6 years old). It was never commissioned properly and was left with the SUNVIC valve in the "flush" position - took me a little while to work out why the pump was on continuously! The radiators weren't balanced and no inhibitor had been added to the system. After a visit from the Vokera agent at least the boiler worked properly. The state of it all did not inspire confidence in me and I wondered whether they'd fitted two valves by mistake or just to confuse me. I'm an electrical/electronics engineer by trade so I understand the sparky bits. If it's anything else I'll have a look but I'm quite happy to get someone who actually knows better to sort it out. End of rant!
Are the valves both 2 port, or 1 a 3 port and the other a 2 port? If the latter, the 2 port is a legal requirement as it will have a spring return to shut the valve in the event of failure, whereas the 3 port can fail open.
I sympathise with you about the state of the system you were left with, but there's plenty of others in the same boat.
As sifu says don't do anything with the unvented tank yourself, get onto the makers and ask for the name of a certified operator to come and service it. This is the one case I think you should ask to see their ticket before they start work. (oops, there's corgi as well). This is because it's illegal for anyone other than certified operators to work on unvented systems larger than 15 litres. I've seen spectacular pictures where an exploded vessel has demolished the building
. That said, these unvented cylinders are safe, as they have 5 safety devices to ensure they are. They should be serviced annually, so it makes sense to get someone with a ticket to do that and your boiler at the same time.
I sympathise with you about the state of the system you were left with, but there's plenty of others in the same boat.
As sifu says don't do anything with the unvented tank yourself, get onto the makers and ask for the name of a certified operator to come and service it. This is the one case I think you should ask to see their ticket before they start work. (oops, there's corgi as well). This is because it's illegal for anyone other than certified operators to work on unvented systems larger than 15 litres. I've seen spectacular pictures where an exploded vessel has demolished the building
. That said, these unvented cylinders are safe, as they have 5 safety devices to ensure they are. They should be serviced annually, so it makes sense to get someone with a ticket to do that and your boiler at the same time.Sponsored Links
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