Grundfos Alpha 1 15-50/60 new pump issues

[D_Hailsham]

Just read this on their website saying the flow arrow should be pointing upwards ...cant understand that the original grundfos was pointing down so i turned the new one to match

That's not a rule; it depends on which way the water has to flow. Pumping upwards is preferable. Provided you have sufficient static head (drop from F&E tank to pump), pumping down is OK.

Now we have established that you have the Ri version, which pipe from the boiler connects to the pump - the left (flow) or right (return)?

 

[Neilk63]

Turning the head does not alter the flow direction in any way, the pump body denotes the flow direction, your pump is upside down

Hi the flow arrow on the last one was pointing down tho and was fitted by British Gas 3 years ago so assuming they f@#$ed up then guys i just took it off replaced the new one to match

 

[Neilk63]

That's not a rule; it depends on which way the water has to flow. Pumping upwards is preferable. Provided you have sufficient static head (drop from F&E tank to pump), pumping down is OK.

Now we have established that you have the Ri version, which pipe from the boiler connects to the pump - the left (flow) or right (return)?

 

[Neilk63]

Can you tell now

The british gas guy is onnway to service boiler I will ask him which way my pump flow arrow needs to be pointing be fuming if he says up when they fitted the last one going down probably the reason it failed after 2.5 yrs

I assume thats why on setring 3 the new pumps stuggling tobgo higher than 26 w when its a 34 w max pump???

 

[Gasguru]

That's a Myson Aerjec at the top...best place is normally in the bin.
They're good at catching debris and they're the first item to cut out when flow issues are encountered...replaced with a simple H pattern using a couple of 22mm equal tees.
You could try a magnet on it...

Plumbing looks ok to me with the pump pumping down (nothing wrong with a pump pumping down providing the feed cistern is sufficiently higher).

What's the setting on the auto bypass valve below...I'm assuming it probably goes 0 to 6 or 0 to 0.6

 

[Neilk63]

Feed cistern is about 5ft above in loft ..had a magnet on boiler when fitted last year

The black plastic thing is the auto bypass i assume pal ...thats set at 0.3

 

[Neilk63]

That's a Myson Aerjec at the top...best place is normally in the bin.
They're good at catching debris
and they're the first item to cut out when flow issues are encountered...replaced with a simple H pattern using a couple of 22mm equal tees.
You could try a magnet on it...

Plumbing looks ok to me with the pump pumping down (nothing wrong with a pump pumping down providing the feed cistern is sufficiently higher).

What's the setting on the auto bypass valve below...I'm assuming it probably goes 0 to 6 or 0 to 0.6

Feed cistern is about 5ft above in loft ..had a magnet on boiler when fitted last year

The black plastic thing is the auto bypass i assume pal ...thats set at 0.3

Is that ok to have flow going down then

Read more: https://www.diynot.com/diy/threads/...0-new-pump-issues.538562/page-2#ixzz6DHMAGwxO

 

[ianmcd]

Hi the flow arrow on the last one was pointing down tho and was fitted by British Gas 3 years ago so assuming they f@#$ed up then guys i just took it off replaced the new one to match

yes the arrow on the pump body should be pointing down

 

[Gasguru]

I meant try a magnet on the Aejec to see how much ferrous debris is in there...but unless you're in the trade it's difficult for a diyer to assess the result.
Yes pump is ok pumping down and bypass setting prob ok...I'm guessing you have a couple of 2 port zone valves.

 

[Neilk63]

I meant try a magnet on the Aejec to see how much ferrous debris is in there...but unless you're in the trade it's difficult for a diyer to assess the result.
Yes pump is ok pumping down and bypass setting prob ok...I'm guessing you have a couple of 2 port zone valves.

Yes mate 2 2 port valves both new when system installed
No idea why pump is humming so much then if everything is set up right maybe just a faulty pump

 

[Neilk63]

I meant try a magnet on the Aejec to see how much ferrous debris is in there...but unless you're in
the trade it's difficult for a diyer to assess the result.
Yes pump is ok pumping down and bypass setting prob ok...I'm guessing you have a couple of 2 port zone valves.

Your not close to Doncaster and want the job do you ?

 

[Gasguru]

Sussex

 

[D_Hailsham]

The right hand pipe should connect to the boiler flow (left connection on boiler).The pipe from the pump should connect to the motorized valves.

Don't worry about how many watts the pump is using. It will vary with the flow rate and required head.

Assuming you need all 24kW, the flow is approx 1000 litres per hour. On speed 3 that gives a head of about 4 metres and about 26W pump consumption. The Ri heat exchanger has a resistance of 2.5m at 1000 litres/sec which leaves 1.5 metres for the rad/cylinder circuit

However you say that the house will still get heated on speed 2, but not so well. This could be because the rads were balanced with the pump set to 3. You would need to rebalance if you set the pump to 2 as the lockshield valves would need to be opened slightly.

 

[Nige F]

Sussex

East or West ? One day I'll need a combi to replace my Floor standing O/F Kingfisher

 

[Neilk63]

The right hand pipe should connect to the boiler flow (left connection on boiler).The pipe from the pump should connect to the motorized valves.

Don't worry about how many watts the pump is using. It will vary with the flow rate and required head.

Assuming you need all 24kW, the flow is approx 1000 litres per hour. On speed 3 that gives a head of about 4 metres and about 26W pump consumption. The Ri heat exchanger has a resistance of 2.5m at 1000 litres/sec which leaves 1.5 metres for the rad/cylinder circuit

However you say that the house will still get heated on speed 2, but not so well. This could be because the rads were balanced with the pump set to 3. You would need to rebalance if you set the pump to 2 as the lockshield valves would need to be opened slightly.

Cheers thats useful i will drop the pump to 2 tomorrow and rebalance the rads ...British Gas guy was hopeless he looked at the pump said yes thats more than adequate for the system had no idea about the 2 question s i asked for the grundfos people just said it was fitted correct flow going right direction but said it shouldn't be that noisy then did one after servicing the boiler‍