flow switch

[raittser]

After months of planning I am about to start installing my heating system.
A mate at work has mentioned that I should install a flow switch. Do not know whether I need this or not as I do not know what its purpose is. He doesn't know either but has one in his system. Am installing conventional boiler (open vent) with valves for h/w and c/h.

 

[taydo]

My suggestion to you is line up the heating engineer who is going to commision the system, and work with him most will be a lot happier to commision your system if they know what you have done is up to spec
dont forget you will need to get building control in.

 

[oilman]

......dont forget you will need to get building control in.

Though why, I don't know. Some of them may know what they're looking at, but I commissioned a system the other day that had been passed by BC and it does not meet current regs. Tank position and fire valve.

Just stuff in whatever you like , they won't care.

 

[PaulAH]

Now, now Oilman. Can this be you speaking?

Not sure what Raittser means by a flow switch. You'll need a couple of motorised valves, operated by a time-switch or programmer, to control the flow to the radiator and hot water circuits.

 

[raittser]

Taydo
Have asked a plumber pal (corgi registered) to commision system. He doesn't know what a flow switch does. Just thought I would try and find out. Won't be getting in B.C.. They were in when I put up my extension. They are a pain in the ****.

 

[drbagiva]

Some conventional boilers now require a flow switch to be fitted when they are connected to plastic pipework{diy style}.Reason being that should an airlock develop the temperatures developed in the boiler can quickly cause catastropic failure of the pipe,especially polybutylene.Have seen this happen on a crazed oil fired combi.

 

[raittser]

Thanks for letting me know the reason for a flow switch. I'm doing my system in copper. You mention that temperatures in the boiler could cause failure of plastic pipe. I thought the overheat thermostat and thermostat sensor would shut down boiler before this could happen.

 

[DP]

All I can say is 'supposed to'. Have been to systems where this not happen as some sensors get bypassed by 'engineer' in desperation while on other systems due to lack of service, sensors may or may not shut the system down safely. You should see the rate of rise of temperature when things go wrong.