Replaced pump & actuator but pump keeps running

[Norv]

My mates heating & hot water system setup, he has got a combi boiler downstairs & a hot water tank & a smal res tank in the airing cupboard. Off these there is x2, 2 port actuators & 1 pump.

The pump & 1 of the hot water actuator needed replacing. Done that but when the heating & hot water is switched off by the timer controller unit the pump keeps running. Is this correct ?

The actuator that we replaced for the hot water is connected through a thermostat built on the side of the hot water tank which stops the flow when the water is up to temp in the tank.

The wiring is a bit of a mess (looks like it was designed by NASA!). The wires off the new actuator are brown(live), blue(N), grey(NC), orange(C), white (which isnt used, i think 22mm pipes), gr/yel(E).

Anyone got any ideas ?

 

[Gasguru]

A combi boiler and an additional pump upstairs...are you sure its a combi. That is not a normal setup.

Normally with a combi the switch contacts in the zone valves will fire up the combi. How is this additional pump connected?

 

[Norv]

Ill get some pics & post on here. The house was built about 10 yrs ago so its not really an old system. It might not be a combi but it definately fires up when it needs to heat the water for the tank & for the central heating.

I'm assuming the pump should run when you need to draw hot water from the tap. i.e its taking it from the tank & pumping it to the tap. Not sure if it should run when the heating is on, but its running all the time at the moment.

 

[corgiman]

Whats the name of the boiler norv?

 

[Softus]

Off these there is x2, 2 port actuators & 1 pump.

And how are these components interconnected. A photo would be handy.

The pump & 1 of the hot water actuator needed replacing.

Why? What were the symptoms of the original problem?

Done that but when the heating & hot water is switched off by the timer controller unit the pump keeps running. Is this correct ?

Is there a secondary circuit? Is there a second timer somewhere?

 

[Norv]

Its a Potterton boiler.

I'm not at the house at the moment. On the hot water side of things, when you set the thermostat on the side of the tank at say 60degs the boiler will run & the pump will pump hot water into the tank until it reaches 60.

For the central heating the boiler will run & the pump will pump water round the rads until the house reaches the temp you set the thermostat in the hallway.

 

[corgiman]

A potterton what mate?

 

[Norv]

Ill get some pics today.

There was a leak & it got into the pump & it was tripping the RCD.

Im going offline now. Thanks for helping

 

[Softus]

when you set the thermostat on the side of the tank at say 60degs the boiler will run & the pump will pump hot water into the tank until it reaches 60.

For the central heating the boiler will run & the pump will pump water round the rads until the house reaches the temp you set the thermostat in the hallway.

This is how it shouldbehave - why are you telling us this?

 

[Space cat]

I'm assuming the pump should run when you need to draw hot water from the tap. i.e its taking it from the tank & pumping it to the tap.

Sorry, just couldn't resist!

If that's the same pump that sends boiler water round the radiators, it also pumps boiler water through a heating coil inside your hot water tank. Boiler water and tap water never mix.

Not sure if it should run when the heating is on, but its running all the time at the moment.

You're right; it should stop when you turn off CH and HW at the controller or when everything is up to temperature. What does the boiler do under these circumstances?

Edit: Here's my best guess based on limited information: When the pump went it took an overrun switch with it. The purpose of the overrun switch is to keep the pump running for a few minutes after the boiler goes off and thus get the residual heat out. It works regardless of programmer settings. Ask your mate to think back. Is that how it used to work?

 

[gas4you]

The wiring is a bit of a mess (looks like it was designed by NASA!). The wires off the new actuator are brown(live), blue(N), grey(NC), orange(C), white (which isnt used, i think 22mm pipes), gr/yel(E).

Don't understand the letters in brackets against the grey and orange wires

Stat call for heat should be connected to brown to open the valve, neutral as is, grey is permanent live to microswitch in valve head and orange is 230V out to pump and boiler switched live for ch from microswitch.

 

[Norv]

Right, here goes

Stat call for heat should be connected to brown to open the valve, neutral as is, grey is permanent live to microswitch in valve head and orange is 230V out to pump and boiler switched live for ch from microswitch

Now I know that, I reckon I got one of the wires wrong, because the old actuator had black going to stat call for heat & brown & grey connected together.