I've just had my hx changed by Vaillant in my 7yr old boiler. The guy that changed it said I had no live feed from the primary circulation pump back to the boiler. He said I should have one as this will allow the boiler to control the pump when the system shuts off via the timer control to allow the heat within the boiler to be removed until the hx temperatures normalised. My circulation pump is a Grundfos ups3 and I have tonight observed that when the timer control switches off, the pump continues to run and circulate for 5 mins before stopping. Will this be sufficient time to normalise the hx temps or will I need a cable running to the boiler? He said because I had no pump overrun controlled by the boiler when the system switched off the water was boiling in the hx and flashing off resulting in my system slowly being topped up with fresh water, which will have accelerated the failing of my hx.
Live feed to boiler from primary circulation pump.
- Thread starter darren6645
- Start date
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It sounds like the pump overrun is wired up, but it's impossible to say without actually being able to see your wiring, and presumably the engineer viewed it in order to make this statement. I'd suggest getting someone in to take a look and install an overrun if one is not present
sorry but your post doesnt really make any sense , if the pump is not wired through the boiler what is supplying the power for it to over run ?
The pump is wired to the boiler, but there is a terminal block within the boiler that says pump and nothing is attached. My understanding from what the engineer said is that control timer is currently controlling my boiler and pump on and off. There should be a live feed from the pump back to the boiler, to the terminal block to accommodate the pump overrun facility in the case where the controller switches the boiler and pump off but residual heat is still present in the boiler. The boiler would override the pump switching off by taking control until the temperatures in and out normalised.
I will try and get a picture.
I will try and get a picture.
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I too have a Vaillant boiler and a Grundfoss UPS 3 pump and when my heating or hot water reaches temperature, my pump also runs for 5 minutes and at the same time that the heating or hot water valve closes, I feel the bypass pipe get hot. Does yours get hot too? I'm presuming that is what is supposed to happen?
There should be a live feed from the Boiler to the pump, but yes that is how it works the boiler decides when the pump runs , but if it is running over as it should then where is it getting the power from ?
but if it is running over as it should then where is it getting the power from ?
I will take a picture of the wiring as soon as I get chance, hopefully that will help.
I will take a picture of the wiring as soon as I get chance, hopefully that will help.
Re-read what you wrote in your first posting....it doesn't make any sense. You say that when the timeclock switches off the pump continues to run for 5 minutes.
The pump feed goes from the BOILER to the PUMP..your terminology is reversed.
The pump feed goes from the BOILER to the PUMP..your terminology is reversed.
I understand what your saying but I was posting what he told me, literally.
The feed needs to come from the boiler to the pump for it to control the pump overrun but my confusion is my pump is running for 5 mins once the timer switches off so do I need this extra wiring.
If the pump is running for 5 mins after the timer switches off then it must be wired to the pump terminal at the boiler (unless someone's been clever and instigated another method).
Post pics of the system, what boiler model etc.
Post pics of the system, what boiler model etc.
Amazing what engineers say and what punters hear
If your suggesting he didn't actually say what I posted then I beg to differ in fact he wrote it down for me. I was only asking a question and wasn't expecting sarcasm. If I didn't need to ask I wouldn't but I thought that's what this forum was for.
Does the boiler always shut off when the timeswitch clicks off (and does the pump always run on for exactly the same duration)? (Just wondering if someones made a boo boo & fed the valve microswitches from timeswitch output)
well please explain where the powere for th pump is coming from then ? I await wit baited breath
Thanks.
I will do that as soon as I can, I'm currently not at home but asap.
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