Delayed switching?

[Rob]

I've got a boiler controlling underfloor heating which is overheating as it fires before the valves have had a chance to open.

Can anyone point me in the direction of a switch which can delay the output? There are wiring centres which have this feature built in but thought this may be an easier solution.

Everything I'm finding seems to be timers for overrun purposes.

Many thanks

 

[Murdochcat]

Shouldn't the valve be supplying the boiler with the switched live

 

[Harry Bloomfield]

I've got a boiler controlling underfloor heating which is overheating as it fires before the valves have had a chance to open.

Normally, boilers and pumps, are triggered on, by the contacts of the valve proving the valve has opened first.

Otherwise, this might be what you need...

GRT8-B1 Mini Power Off Delay Time Relay DIN Rail Type AC/DC 12V~240V Delay Relay | eBay

Relay working status is indicated by LED indicators. Output relay indication: red LED. Power consumption: AC 0.09-3VA/DC 0.05-1.7W. Setting accuracy: 10%. Function: Delay OFF.

www.ebay.co.uk

 

[ericmark]

Our John Ward does a video on have the motorised valves work which have a micro switch built in however, I have had the micro switch fail in the on position, that is the most likely fail, the spring is just not strong enough when some dust etc. builds up over time.

This can cause the pump to burn out, if plumbing is not correct, the by-pass valve should be between the pump and motorised valve, so if the micro switch sticks, the by-pass valve opens and the water circulates through the boiler, but I know my pumps and motorised valves are on the return, god I am sure knows why, so there is no by-pass valve as no pressure to open one.

The standard with under floor heating is the hot water from the boiler is pumped for all heating areas and a second pump circulates water under the floor, the idea is radiators need water at around 70ºC where the floor needs water at around 27ºC the floor temperature depends on floor type.

Delay start was a standard feature of a star/delta motor starter, so there are loads around, but things made for industry tend to have a high price tag.

So it is likely not a good option,

they are still around, but silly prices.

 

[SUNRAY]

A lot depends on the valves, if you have a manifold with a number of zone valves there is a good chance they don't have microswitches, in fact they may be extra low voltage wax actuators and very small such as these https://www.underfloorstore.co.uk/product/warmup-whs-m-s3-act230-230v-actuator.
The manifold may have a pressure or pressure differential switch which should be incorporated into the boiler operation.

However, these are OK: https://www.ebay.co.uk/itm/326147541800? at £9