Any good problem solvers out there?

[grahamdvd]

Hi
I have a Salamander RHP 75 fitted to my hot and cold water system. It's been fitted 10 years and pumps my hot and cold water to my basins, showers and baths.

It started making some strange noises, it was worse if you ran a bath upstairs and turned on the kitchen tap at same time. It got worse and worse until sometimes any hot tap turned on it groaned and stopped and started and Hardly any water came out.

I did find that if you turned on a pumped tank fed cold water tap on same mixer at the same time as the groaning hot water tap it stopped the groaning, then after 1 min you could turn off the cold tap and the pumped hot water was fine.

In the end I thought it's got to be the pump so I bought a new one, fitted it and turned a tap on and it's just the same?

What could be making the pump groan like mad?

It's a gravity fed system, the pump is just above the cylinder, there's a anti gravity loop fitted just before the pump from the hot water cylinder. It's a full house Salamander RHP 75 pump.

I have had three plumbers round and they all scratched their heads and said I'll get back to you!

Many thanks

 

[oilboffin]

I think that you may have a bearing starting to go so keep an eye on it.Bob

 

[picasso]

Have the temp of the hot water checked, should be max 60c at pump inlet.

 

[grahamdvd]

The pump is brand new, it sometimes works for a few days, then makes a strange noise and the only way to stop it making the noise is to turn a cold pumped tap on?

Why turning the cold tap on would it stop the pump making me he noise?

Thanks

 

[grahamdvd]

I've checked the cylinder thermostat and it's set at 60 degrees, I did turn it down more until my wife complained that the water was Luke warm and it still made the noise?

Thanks

 

[picasso]

See if the hot water expansion pipe has gotten submerged in the cold water cistern, other than that no idea.

 

[grahamdvd]

I checked that, I even flushed out from cold water header tank to cylinder and then put a new salamander s flange on.

Then cleaned out pipe work from top of cylinder to pump, So all pipe work from hot water header tank to pump is clean.

Where could it be sucking air in ? If it is air? When it's having a bad day, when you turn a tap off the pump runs for 5 seconds, before it used to shut off straight away thanks

 

[grahamdvd]

Does anybody know how the salamander pumps work? I know about the flow switches etc

But how does the little pipe that connects the cold side to the hot side work?

There is one motor but two propellers, so if you turn on the cold side how does it not pump out hot water etc?

I'm trying to get my head around what would be the cause of when the hot side is running and making a noise you turn the cold side on and it stops making the noise? Thanks

 

[Jajodu]

when the pump was changed were the Flexi hoses also replaced?

 

[Jajodu]

A pic of the pump and plumbing would be helpful

 

[grahamdvd]

Yes the new pump came with new hoses so they were used.

 

[Jajodu]

When mine played up a few years ago it was due to a stuck auto air vent.

 

[grahamdvd]

As I said it can work for a few days and then suddenly not work, just groaning, stopping and starting, only a little water coming out, then you turn a pumped cold tap on and it works?

I've just read about the Salamander RHP pumps it seems they have a bypass loop, since they have one motor and two propellers. It's for when you use only one side and stops the non open one running dry?

 

[picasso]

As you have checked the hot inlet pipework to the pump it could be a problem with the supply to the cylinder, gate valve not properly opened, scale if you have hard water ect.

 

[grahamdvd]

Hi thanks, but how would I check that?

There is a gate valve on the supply to the cylinder but it not been touched for years.

But why would running the cold water tap make the pump work ok?

Thanks