Which is the more powerful pump?

[rcpilot]

Hi all just picking your brains 2 pumps with flow rates of 3.8 and 5.7 which is the more powerful, also can you fit a commercial pump into a domestic system?

 

[John.g]

Just note the pump power as above "Have a careful look at the pump power as its possible that its pumping 0.65m3/hr (10.8LPM), if so the pump power will be 34W so carefully note this and then briefly shut the pump outlet valve and again note the power.

Even if you installed a 10M pump the flowrate (if any) will only increase by 30% (sqroot 10/6) so maybe from 10.8LPM to 14.0LPM, so checkout the power please.

Also if you only now changed to 100% CC from PP3 then the flowrate would only have been 7.9LPM at 3.15M. assuming the pump is running at 34w above.

 

[rcpilot]

Hi John thanks for your input, I need to shut down (my head is spinning from all that's going on) so as I told you I am getting on a bit, would it be possible to give me the settings for the pump so as to obtain the measurements you require, then I will shut the outlet down and record the settings again and we can take it from there thanks.

 

[John.g]

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

 

[Ben-gee]

I’m fairly sure this is a balancing problem.

 

[rcpilot]

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

OK, (I'm getting on a good bit more than you).

Just put or leave the pump in CC (constant curve) mode at 100% which is the highest possible setting that will give the greatest circulation.

Leave what ever rads you have open to the circuit now and just start the boiler/pump and note the pump head in (meters) M, the flowrate in M3/hr and the most important one of all the power output in (watts) W. and then just shut the pump outlet valve for say 5 secs (boiler/pump running) and just note the above readings again, re open the pump outlet valve and if desired then shut down the boiler/pump. You may wish to post the first set of readings before doing the closed valve test.

Hi thanks John I get tired very easily these days with the problems associated with me being diabetic and problems with my knees and arms, I never thought that having arthritis in my arms would feel like I had bad toothache but it does with me been to the dentist and he pointed this out to me, will talk with you tomorrow if that is ok with you, got to get this sorted out before the cold weather sets in as this is another problem with being diabetic I cannot stand the cold, never mind.

 

[rcpilot]

Hi thanks John I get tired very easily these days with the problems associated with me being diabetic and problems with my knees and arms, I never thought that having arthritis in my arms would feel like I had bad toothache but it does with me been to the dentist and he pointed this out to me, will talk with you tomorrow if that is ok with you, got to get this sorted out before the cold weather sets in as this is another problem with being diabetic I cannot stand the cold, never mind.

 

[rcpilot]

Good morning John
Did like you said and the results from closing the outlet of the pump were no different than the previous results namely :- estimated pump head 5.9M, flow rate 0.0m3/h, power output 22watts

 

[John.g]

Just to be clear
Pump definitely in CC3 mode and results with the pump outlet open were the same as with it closed, above, ie, 5.9M, flow rate 0.0m3/h, power output 22watts??, extraordinary as you are getting some circulation through the rads.
Also check that the pump inlet valve is fully open.
Just confirm the above please and I will have another look through the pump manual

 

[John.g]

Have you still got the Alpha 2 pump?

 

[rcpilot]

Just to be clear
Pump definitely in CC3 mode and results with the pump outlet open were the same as with it closed, above, ie, 5.9M, flow rate 0.0m3/h, power output 22watts??, extraordinary as you are getting some circulation through the rads.
Also check that the pump inlet valve is fully open.
Just confirm the above please and I will have another look through the pump manual

Yes John exactly the same, I had the same query how come the downstairs big radiator (upstairs closed) was heating up with a flow rate of 0.0m3/h dos'nt seem possible, the system is a sealed fully pumped "Y" plan
one

 

[John.g]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

 

[rcpilot]

Have you still got the Alpha 2 pump?

yes I have, another thing could my problems be associated with the outlet valve, why I say that is because the pump has the common connections on it but I have a gate valve just above it and I have been using that to close off the outlet and I have had problems with that type of gate valve before where the brass gate dose not fully open or fully close but sticks in one position.

 

[rcpilot]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

Do you think that if I flushed out the whole system with a good cleaner it might do the trick?

 

[rcpilot]

Doesn't seem possible, can you change to constant pressure mode CP3 which is a constant 4.5M, if not pumping in this mode then the power will read only 15W.

I did come across here sometime where a pump was displaying all the above symptoms but when the head was removed it was full of soft sludge with the impeller vanes choked, vanes can be cleaned with a tie wrap.

If its still not pumping on CP3, I would be inclined to isolate the pump and remove its head (2 or 4 stud bolts) complete with impeller and inspect it, then flush pump body ports alernatively tfrom he inlet and outlet valves, you will have to top up the boiler afterwards.

OR, if you still have the Alpha 2, simply install that and see will it pump, why did you replace it with the Alpha 3 as it has exactly the same performance but not the same amount of bells and whistles
If this pump was installed originally then you can look at this first for any signs of sludge inside, etc.

i did notice you mentioned CP3, the pump was set in constant curve, so I reset it to CP3 closed the valve and the pump stopped, reopened it and the pump reset itself to constant curve, i have been using my wifes new phone but it keeps losing the connection with the pump and is very hard to reconnect

 

[John.g]

yes I have, another thing could my problems be associated with the outlet valve, why I say that is because the pump has the common connections on it but I have a gate valve just above it and I have been using that to close off the outlet and I have had problems with that type of gate valve before where the brass gate dose not fully open or fully close but sticks in one position.

Yes, a prime suspect, its quite possibly closed now so if the threads arn,t stripped you should get 3 to 5 full turns anticlockwise from it , there's always a 1/2 to 3/4 of free play before they start to open or close.

Do you think that if I flushed out the whole system with a good cleaner it might do the trick?

Only as a very last resort IMO, get the pump working and we can see then if required.

If you do get it opened then leave it as Don,t require any more closed valve readings

 

[rcpilot]

Yes, a prime suspect, its quite possibly closed now so if the threads arn,t stripped you should get 3 to 5 full turns anticlockwise from it , there's always a 1/2 to 3/4 of free play before they start to open or close.


Only as a very last resort IMO, get the pump working and we can see then if required.

If you do get it opened then leave it as Don,t require any more closed valve readings

Ok John I will strip the Alpha3 out check the gate valve, if it is ok I will put the Alpha 2 back in to see if that makes any difference, will get back to you when it's done could be a few days, one thing I forgot to tell you is I suffer from a back problem, when I was working as a service engineer for a firm that serviced and repaired lifts,hoists cranes etc I fell off an overhead crane over in Carlisle many years ago and I back pain when i do too much

 

[John.g]

Did you manage to open it, remove handwheel and use a adjustable spanner as a lever.

Maybe just renew the gate valve and take from there, you can always check pumps later as you can isolate them?

 

[rcpilot]

Did you manage to open it, remove handwheel and use a adjustable spanner as a lever.

Maybe just renew the gate valve and take from there, you can always check pumps later as you can isolate them?

Hi john well striped the Alpha 3 out and guess what, both valves were barely open so that was the restriction to flow, I renewed some of the pipe work to one of the radiators because it had a service valve on it and it was leaking and I am now cleaning up after the work, if everything is hunky dory with the system what is the best setting for the Alpha 3 and I might try to balance it with the go balance app.
Ken

 

[John.g]

That's good news Ken, I would set it to CC3 to start with, if you have to close all the rad valves individually (no u/staors/d/stairs zoning), then just run it as is, ie, if d/stairs only opened up now just start the pump and post the numbers, you can then open up the u/stairs and run both systems together on CC3 and have a look at those numbers.
Don't know what the total rad(s) output is but assuming 20kw max then the flowrate required will be 20LPM (1.2M3/hr) at a rad dT of 14/15C/kw which would result in a pump head of 4.7M in CC3 mode, see what you come up with anyway and you can decide on balancing, if any, is required later.

My system, 12 rads, 20kw, no balancing, works fine at a 3.5M head.

 

[rcpilot]

That's good news Ken, I would set it to CC3 to start with, if you have to close all the rad valves individually (no u/staors/d/stairs zoning), then just run it as is, ie, if d/stairs only opened up now just start the pump and post the numbers, you can then open up the u/stairs and run both systems together on CC3 and have a look at those numbers.
Don't know what the total rad(s) output is but assuming 20kw max then the flowrate required will be 20LPM (1.2M3/hr) at a rad dT of 14/15C/kw which would result in a pump head of 4.7M in CC3 mode, see what you come up with anyway and you can decide on balancing, if any, is required later.

My system, 12 rads, 20kw, no balancing, works fine at a 3.5M head.

I have bled all the rads but left the kitchen one out of it for the time being, the bathroom towel rails are getting mad hot and the sitting room is starting to heat up, nothing yet in the bedrooms but I suppose balancing will bring them up

 

[John.g]

With CC3?
What pump values are you getting?

 

[John.g]

You said in post #1 that the upstairs rads were heating but not downstairs?,
If you have a Y system with a mid position valve then just carry out the basic check that the pump arrow is pointing towards it, also ensure that system is pressurized to 1.3/1.5 bar.
Can you also take pump values with DHW heating only on, then with (eventually) DHW+d/Stairs+U/stairs.

 

[rcpilot]

You said in post #1 that the upstairs rads were heating but not downstairs?,
If you have a Y system with a mid position valve then just carry out the basic check that the pump arrow is pointing towards it, also ensure that system is pressurized to 1.3/1.5 bar.
Can you also take pump values with DHW heating only on, then with (eventually) DHW+d/Stairs+U/stairs.

Hi John, this flaming thing has got me demented, when I put everything back together, filled the system, bled the radiators, then started it up it was showing 24 watts on the pump and I think 0.6m3/h and the towel rads were getting mad hot the big rad downstairs was getting hot, both bedrooms were cold obviously because the lockshields were closed, the entrance rad was still cold, so I turned it off. Today I turned it back on and got the same results, so I started to manually balance the towel rails got them somewhere near the 12 deg difference checked the pump and the wattage had gone down to 15 and the m3/h was showing 0.0, hair now all over the floor.

 

[rcpilot]

Hi John, this flaming thing has got me demented, when I put everything back together, filled the system, bled the radiators, then started it up it was showing 24 watts on the pump and I think 0.6m3/h and the towel rads were getting mad hot the big rad downstairs was getting hot, both bedrooms were cold obviously because the lockshields were closed, the entrance rad was still cold, so I turned it off. Today I turned it back on and got the same results, so I started to manually balance the towel rails got them somewhere near the 12 deg difference checked the pump and the wattage had gone down to 15 and the m3/h was showing 0.0, hair now all over the floor.

Hi John decided to check the pump with the "go remote app" that pump has got a mind of it's own it reset itself from CC to CP so I reset it to CC and operating @ max it went back to showing 24 watts but the flow rate remained @ 0.0m3/h

 

[John.g]

Balancing should be the last thing to do IMO.
Can you just run on DHW and check values as this is practically a short circuit through the cylinder coil where most of the short? run will/should be in 22mm, if there is a balancing gate valve on the coil return, just open it fully.
I would expect to see ~ 34W on CC3.