Can Grundfos UPS2 fail slowly?

[bizzlebest]

Hi there,

I have a grundfos ups2 whirring away and it takes ages to warm up the rads in my house, and then only to a lukewarm temperature. When i turn off all the TRVs upstairs to push heat downstairs, the rads down there get hotter, but again they take ages to warm up. The pipes out of 3 way mid-valve are molten hot going to central heating and lukewarm to hot water cylinder, so i know the valve is alright. So the heat is there and heading in the right direction.

Do I need a new pump? or is this a boiler problem? I've desludged our system recently and my in-line filter isnt bringing out much magnetite.

Cheers in advance

 

[ShaunCorbs]

Sounds like it’s slowing

Have you checked the pump and valves incase there restricted ?

 

[John.g]

Also check pump settings/mode.

 

[bizzlebest]

Sounds like it’s slowing

Have you checked the pump and valves incase there restricted ?

it all appears to be unrestricted, the pump sounds like its working away. I thought pumps either work or dont work 😂

 

[bizzlebest]

Also check pump settings/mode.

It was on 2 but i've put it on 3. Putting it on 3 stops the boiler giving an F23 error (temp differential between flow and return on being greater than 35 degrees - Vaillant boiler) this doesnt make rads get any hotter though

 

[John.g]

It was on 2 but i've put it on 3. Putting it on 3 stops the boiler giving an F23 error (temp differential between flow and return on being greater than 35 degrees - Vaillant boiler) this doesnt make rads get any hotter though

If the pump is performing normally on constant curve 3 and assuming the boiler's min output (max turndown) is 6kw then a flowrate of < 0.2M3/hr (0.17) will keep the flow/return dT to 30C and will have a head of 6M so either faulty pump or severe restriction somewhere?, if the F23 is happening during burner fire up then a flowrate of ~ 0.5M3/hr required but the pump head should still be 6M at this flowrate. If, as you say, the mid position valve is OK then can't see why the water temp should only be lukewarm to the HW cylinder coil especially in the mid position of CH&DHW selected.

 

[Bizzlebest1]

If the pump is performing normally on constant curve 3 and assuming the boiler's min output (max turndown) is 6kw then a flowrate of < 0.2M3/hr (0.17) will keep the flow/return dT to 30C and will have a head of 6M so either faulty pump or severe restriction somewhere?, if the F23 is happening during burner fire up then a flowrate of ~ 0.5M3/hr required but the pump head should still be 6M at this flowrate. If, as you say, the mid position valve is OK then can't see why the water temp should only be lukewarm to the HW cylinder coil especially in the mid position of CH&DHW selected.

Thanks for the reply John. Sorry what I meant was that the mid position valve was on CH only with HW off. This meant the pipework from my new mid position valve was molten heading off to the rads and lukewarm on the HW pipework from the mid position valve. So I know the hot water is heading round the CH circuit but it's not getting my rads hot enough. I just used a magnet to see if there was any magnetite build up, and the magnet found something on the u bend before the pump! Obviously my x400 hasnt shifted it! The pipework in my airing cupboard doesn't make sense to me, could I post a pic and get your input on whether it's dodgy or not please? Many thanks

 

[bizzlebest]

So this is the upstairs Airing cupboard, boiler downstairs in the kitchen. I cant make heads or tails of it. The copper pipe from before the pump, round the ubend and half way up is all sticking to a magnet. Is that a normal place for magnetite to be? Also is that Fernox TF1 in the right place? Many thanks

 

[John.g]

There should be a arrow on the pump body, is it pointing up or down, also you might answer the query in the attachment.

 

[bizzlebest]

There should be a arrow on the pump body, is it pointing up or down, also you might answer the query in the attachment.

Hi John, thanks for the reply.

The arrow on the pump is pointing upwards towards the mid point valve.

To answer your query, That dodgy plastic pipework is coming out from the shower pump, the grey piping goes off through the wall to the shower on the other side. Unless your comment is about the HWC return valve.

Cheers

 

[John.g]

So the magnetic filter is only on the return from the HW cylinder coil?, is this the only one in the whole system and when/why was it installed?. Is the system sealed with a expansion vessel or open vented with a header tank?.

 

[ShaunCorbs]

So the magnetic filter is only on the return from the HW cylinder coil?, is this the only one in the whole system and when/why was it installed?. Is the system sealed with a expansion vessel or open vented with a header tank?.

No flow from the boiler

Header tank

 

[John.g]

No flow from the boiler

Header tank

OK making a bit of sense now, so boiler, mag.filter, vent, cold feed, pump then m.position valve.
Has the magnetic filter been cleaned recently?, if not there from day one then possible blockage around the vent/cold feed area, if no blockage here and if the pump is performing OK then would expect pump over through vent or back through cold feed, have a look in the F&E tank for any pump over or movement in the tank, also watch it while getting someone to stop/start the boiler/circ pump.

 

[bizzlebest]

No flow from the boiler

Header tank

OK making a bit of sense now, so boiler, mag.filter, vent, cold feed, pump then m.position valve.
Has the magnetic filter been cleaned recently?, if not there from day one then possible blockage around the vent/cold feed area, if no blockage here and if the pump is performing OK then would expect pump over through vent or back through cold feed, have a look in the F&E tank for any pump over or movement in the tank, also watch it while getting someone to stop/start the boiler/circ pump.

So the boiler pumps up through the mag filter and onwards to the pump. Should the filter not be before the boiler? Or is that being idealistic. Anyhow, the filter appears clean at the moment, I do it twice weekly.
How would I go about unblocking this? Cutting it out and cleaning it then using compression couplers to it back on? Thanks so much for your time. It's much appreciated.

 

[ShaunCorbs]

Easy way to test remove the pump and open the bottom pump valve a smidge see if any water flows

 

[John.g]

And to state the obvious, check water level in F&E tank.

 

[bizzlebest]

Easy way to test remove the pump and open the bottom pump valve a smidge see if any water flows

Thanks for the reply Shaun, must'nt there be some water flow through that bottom pump valve already as it does heat the HWC and radiators? It just does it very slowly and giving f23 errors on boiler. Cheers

 

[John.g]

So the boiler pumps up through the mag filter and onwards to the pump. Should the filter not be before the boiler? Or is that being idealistic. Anyhow, the filter appears clean at the moment, I do it twice weekly.
How would I go about unblocking this? Cutting it out and cleaning it then using compression couplers to it back on? Thanks so much for your time. It's much appreciated.

Ideally, yes the filter should be on the return just before the boiler. It would be very unusual to have two pumps in the system if this is what you are inferring by saying the "boiler pumps up through the mag.filter."
You should carry out the suggestion above by draining off some water and see if the ball cock starts making up water into the F&E tank as rapidly as its being drained off, that will show if the cold feed is clear, at least

Should also have asked if HW circulates without alarming if HW only selected, esure the red gate valve on the coil return is at least 1 full turrn open.