difference in pump sizes

[Meme21]

Hi - I have been told today, by a different gas engineer that I have a 15-50 central heating pump and that as I have 22 radiators it is insufficient and it should be upgraded to a 15-60.

My question is would a 15-60 pump be sufficient or would I need to go for something even larger.

Thanks

Val

 

[D_Hailsham]

Hi - I have been told today, by a different gas engineer that I have a 15-50 central heating pump and that as I have 22 radiators it is insufficient and it should be upgraded to a 15-60.

Why does the engineer think your 15/50 pump is too small? What problems are you experiencing?

The number of of rads is not the deciding factor. The size of pump depends on how much heat has to be delivered as well as the size and arrangement of the pipes.

 

[Meme21]

I have a couple of radiators that were fitted to an extension. They have always been very slow to heat up and since my new boiler (a Worcester Bosch 40 cdi) was fitted one is almost cold. I also have a very very long run of radiators from one end of the house to the other. He suspects that I have some sludge in some radiators as well even though the engineer who fitted the boiler invoiced for flushing of the system (not quite sure what this means - don't think it was power flushed.)

He also said that when the boiler was fitted I should have had a non return valve put in the airing cupboard and alterations made to - sorry but this is not very technical - some H pipe work in the airing cupboard as well which is causing air to be sucked into the system. I fully believe him with regard to the non return valve as that was mentioned in another more expensive quotation for the boiler fitting which I wish I had gone with now. Also I have been having to vent some of my radiators quite regularly so wonder if this H pipe work has always been a problem. Anyway he really seemed to know what he was doing as has balanced my system well (which should have been done before).

He suggested that something even bigger than a 15-60 would be appropriate but that it would mean changing the pipe work and that a 15-60 should do it. Just wondered what the difference would be if I had something even larger.

Thanks

Val

 

[Nige F]

I personally H ave never been impressed by a H layout ...thought it was just a cheap way of doing pipework . Basically it creates a neutral point in the systen -neither + or - pump pressure with the relationship of pump/ vent/ cold feed.

 

[Meme21]

[/quote]Me too [/quote]

LOL

 

[Agile]

Are you able to measure the flow and return pipes at trhe boiler when the heating has been on for an hour or two?

On some Vaillants you can do that from the diagnostic settings on the boiler.

That will indicate if the pump is undersized for the installation.

Not often I say so, but most of Hailsham's posting are very informative for someone who is not working in our industry. I would say that he will probably give a better reply than 19 out of 20 "plumbers" and his grammar and spelling are probably better that 29 out of 30 !

Tony

 

[Meme21]

No - am not able to do this. System was balanced and cold radiator was hot for a while - has now gone cold again It is in downstairs bathroom on a spur from an upstairs radiator. Other radiators that were cold at the bottom are now fine, but this one is just a problem.

 

[D_Hailsham]

I personally H ave never been impressed by a H layout ...thought it was just a cheap way of doing pipework . Basically it creates a neutral point in the systen -neither + or - pump pressure with the relationship of pump/ vent/ cold feed.

I know what a 3T layout is and a 4T-2T; but what is an H layout? Is it anything like this?

[code:1]

Vent Cold Feed
|| ||
|| ||
|| ||
|================= |
|| ||
|| ||
|| ||
Boiler Pump
[/code:1]

 

[D_Hailsham]

his grammar and spelling are probably better that 29 out of 30 !

Thats wot appens when u go to a skool wot teeches proper like, init?.


PS and a good spell checker in Firefox which highlights as you write.

 

[Biggles..]

I prefer a H frame to an arjec anyday of the week, that said i prefer pumped return.

I would have thought that if your installer has sized your system at 40KW like your boiler then your pump is undersized and so is a 15/60. The pump you have is suitable upto about 30KW after that they struggle shifting the heat.

Even with 22 rads at a minimum of 1KW your getting to the borders of your pump, these are are based on generalisations rather than flow and resistance calculations.

I personally would have expected a 25-55 based around a 40KW system.
But here lies your problem, a 15/50 or 60 is 130mm flange to flange, a 25-55 or 60 is 180mm flange to flange requiring some alteration to your pipe ork.

If your altering the pipe ork to suit a bigger pump why not consider removing the cold feed/open vent and converting to a sealed system.
This tends to help a pumps performance and also will stop system degredation.

 

[mcmarshon]

Hey Val, who the hell installed your system ?

First problems with the gas, now pumps and radiators. I recall you paid about £4,500 and you don't seem to have a properly installed system ?

Is this a DIY or non-registered installation ?

I wouldn't be happy paying out that amount for a half done job.

 

[gassafeman]

Hey Val, who the hell installed your system ?

First problems with the gas, now pumps and radiators. I recall you paid about £4,500 and you don't seem to have a properly installed system ?

Is this a DIY or non-registered installation ?

I wouldn't be happy paying out that amount for a half done job.

I guess you have read the same as myself. Any decent RGI would have dealt with all these problems at the source.
1. The gas pipe would be sized correctly.
2. A proper flush would have been done.
3. A suitable pump would have been installed (especially if the old one was full of crap).

To the OP, 4 and half large and your questioning everything he has done?

Its of couse a NON RGI Installation, and we are left answering the questions as the Installer obviously cant.

Its the Citizens Advice Beauro for numpties who cant complete a decent job.

Paul

 

[Meme21]

Hm - I got a Gas Safe engineer to install the boiler. He was recommended to me and was cheaper than another quote I got. He put the boiler in very quickly but then (and this wasn't his fault) couldn't commission it because of low gas pressure. I had a lot of work done by the gas supplier and my engineer kept coming back and saying he still couldn't commission it. I then found the information re: 2.5 mb difference between meter and boiler and it was commissioned and off he went.

He said he had flushed the system prior to the problems with the gas pressure, but then I lot of new pipes were put in. Long and the short of it is that my hot water isn't heating as well as it was, some my radiators are cold at the bottom and one doesn't work at all.

I don't really want to go back to him and asked another engineer recommended by a reliable neighbour round today. He has balanced the radiators as well as he can, but suggests that other work should have been carried out, not the least of which is a non return valve. He further suggests that after Christmas I ask Worcester Bosch to come out to examine the installation, although he didn't see anything obviously wrong himself. He said that if WB found a problem they would put it in writing and then I can take it to whoever hasn't done the job properly.

I am getting the 15-60 pump installed tomorrow but have been told that it will suck in a little more air than at present. He will then come back after New Year and put in the valve and do something with the H pipework so that I don't have the air sucking problem any more.

It has all been a bit of a nightmare for which I have paid a small fortune, but hopefully there is light at the end of the tunnel.

So hard to know who you can trust. I thought if someone was on the Gas Safe register that would be enough, but perhaps it isn't.

 

[mcmarshon]

What is his gas safe i.d. number ?

 

[gassafeman]

Hm - I got a Gas Safe engineer to install the boiler. He was recommended to me and was cheaper than another quote I got.]

Because he has no idea what he is doing.

He put the boiler in very quickly but then (and this wasn't his fault) couldn't commission it because of low gas pressure.

As above. Any RGI would have dealt with that immediately.

I had a lot of work done by the gas supplier and my engineer kept coming back and saying he still couldn't commission it. I then found the information re: 2.5 mb difference between meter and boiler and it was commissioned and off he went.

You did his job for him!

He said he had flushed the system prior to the problems with the gas pressure, but then I lot of new pipes were put in. Long and the short of it is that my hot water isn't heating as well as it was, some my radiators are cold at the bottom and one doesn't work at all.

So, he cant even clean a system properly.

I don't really want to go back to him

Im not surprised. He's crap.

He has balanced the radiators as well as he can, but suggests that other work should have been carried out, not the least of which is a non return valve. He further suggests that after Christmas I ask Worcester Bosch to come out to examine the installation, although he didn't see anything obviously wrong himself. He said that if WB found a problem they would put it in writing and then I can take it to whoever hasn't done the job properly.

On the whole....

EDIT.

And put the non-return valve where?

Im not aware that your boiler manufacturer will come out to 'check he's done it right' FOC! Your going to have to pay for that. About £260.