How to tell if you have Gravity or Pumped HW?

[SteveP86]

Hi Guys

I was just wondering how to tell what setup you have if you can't get access to pump, valves etc without pulling up carpet.

If I put my hand on the pipe leading to the HW tank coil (when cold obv) I can feel the water being pumped through it if I have both CH & HW turned on yet if it's just HW turned on I don't feel the water being pumped. I got a new programmer fitted and the plumber isn't coming till Wed to check over system as per my older post I'm getting loud banging from the boiler if I only have HW on. I saw in the Programmer manual there's a jumper for either pumped or gravity but was just wondering if it's normal for gravity hot water to become pumped only when heating on too or if gravity never gets pumped regardless if heating is on or off.

I don't want to mess with jumpers or ever pull off face plate as that's an experts domain and not mine - I'm a copier engineer, not a heating engineer!

Any opinions or thoughts from you fine experts would be great

Many thanks

Steve

 

[stardanny]

Hi Steve

What boiler do you have? If it is a back boiler, pump might be at side of chimney breast?

Is the cylinder primary flow and return a 28mm ? The one on side middle, one lower the same side.

Daniel.

 

[SteveP86]

Hi Steve

What boiler do you have? If it is a back boiler, pump might be at side of chimney breast?

Is the cylinder primary flow and return a 28mm ? The one on side middle, one lower the same side.

Daniel.

Hi Daniel

We have a baxi back boiler. Crawling around on the living room floor I think I can hear the slightest hum under the floorboards near the pipes that run up the side of the chimney. I was sure the pump was in the upstairs bedroom but I can only find two fat pipes coming up from down stairs leading off to the hot water tank in the next room and two thin pipes coming up from downstairs leading off to all the rads
this is the thickness of pipe for the HW tank coil

Untitled

• SteveP86
• 9 Mar 2014
• 1

 

[stardanny]

What you have is gravity HW and pumped heating.

The pump with the thin pipe is somewhere on side of chimney breast where the boiler is.

Maybe inside box over.

The valve next to tank, I can't remember what it called, I should know, i fitted many..... :-/

That's it, Cyltrol valve!

Daniel.

 

[SteveP86]

What you have is gravity HW and pumped heating.

The pump with the thin pipe is somewhere on side of chimney breast where the boiler is.

Maybe inside box over.

The valve next to tank, I can't remember what it called, I should know, i fitted many..... :-/

Daniel.

On gravity HW is the water pumped through the tank coil when CH is on? Is that the norm?

How can I silence the dreadful banging from the boiler when just asking for HW?

 

[Whitespirit66]

You risk damage to your boiler, as the banging is caused by bad circulation, etc and heat not being taken away from it to cylinder. If you have an electric immersion heater, use that until your engineer arrives.

I would tryto avoid using boiler alltogether, but certainly don't use hw if it causes banging.

 

[stardanny]

As you have a baxi back boiler, it has an injecter tee so when HW is on only, the boiler come on, pump stay off, and the pipes from boiler to cylinder work on thermodynamics ( think it right? ), heat rise up and cold drop down, that why it is gravity.

Pump come on for heating and the injecter tee help gravity move a little quicker.

Might want to get the boiler serviced... It might be overheating on gravity only...possible Cyltrol valve seized....

Daniel.

 

[SteveP86]

As you have a baxi back boiler, it has an injecter tee so when HW is on only, the boiler come on, pump stay off, and the pipes from boiler to cylinder work on thermodynamics ( think it right? ), heat rise up and cold drop down, that why it is gravity.

Pump come on for heating and the injecter tee help gravity move a little quicker.

Might want to get the boiler serviced... It might be overheating on gravity only...possible Cyltrol valve seized....

Daniel.

Thanks guys

Just had it serviced and was told working a treat. I understand now that the pump is just helping out with the tank now.

To be fair I only reported the heating timer being the fault so the chap had no reason to test other stuff.

Do you suspect being pipes from the 70's I'll be told that it's down to sludge in the pipework restricting the flow?

This is a microbore system with two port rad valves and I'm told you cant powerflush these types of valves so who knows what I'll do if that's the problem.

Thanks

Steve

 

[stardanny]

Never heard of can't power flush rad with 2 port rad valve.

I usually rip microbore system out on replacement work.

That is quite old, have you ever thought about new system? New boiler, cylinder and radiators/pipework?

Daniel.

 

[SteveP86]

Never heard of can't power flush rad with 2 port rad valve.

I usually rip microbore system out on replacement work.

That is quite old, have you ever thought about new system? New boiler, cylinder and radiators/pipework?

Daniel.

Yes

New rads, pipes and boiler would be nice. Dunno what I prefer - conventional or combi. Also being skint doesn't help hah! Perhaps converting to fully pumped would be better?

What would the cost be for a plumber to convert the sys to fully pumped?

Steve