Gravity fed hw system

[zeebeedee]

I have little experience on these old systems. A mates bought a house with the setup shown. Had a quick look today, heating on boiler and pump fires rads heat up. Hw only pump goes off boiler cycles, flow gets red hot returns cold. Any ideas?

 

[zeebeedee]

The hw tank is directly above the boiler. Is this normal for gravity hw set up?

 

[Ch4 plumbing]

Pumped heating gravity hot water, I've only ever seen gravity hot water with 28mm pipe work though.

 

[Ermintrude]

Yes Normal for grav. But don't think that boiler is designed for grav hw. It should be a fully pumped system i would just bosh in a two port and a bypass - gate vale

 

[zeebeedee]

Pumped heating gravity hot water, I've only ever seen gravity hot water with 28mm pipe work though.

If you look its 22 off the boiler to 28 to the cylinder.

 

[Ch4 plumbing]

Yep I can see that now, teach me to take a quick look and start flapping my gums :90:

 

[zeebeedee]

Yes Normal for grav. But don't think that boiler is designed for grav hw. It should be a fully pumped system i would just bosh in a two port and a bypass - gate vale

Thats what I suggested would be easy enough 2 port on the flow to the heating circuit.

Will be be done in the near future he's having the damp sorted first and kitchen/bathroom done. In the meantime any ideas on how to stop the boiler cycling for now?

 

[Ermintrude]

Move the pump? Or turn boiler down low?

 

[Ermintrude]

When you say having damp sorted not got the injection cowboys in has he? The solution is not injection it's ventilation.

 

[zeebeedee]

When you say having damp sorted not got the injection cowboys in has he? The solution is not injection it's ventilation.

No a builder mate of ours is doing it, cowboys where in previously "injecting" for the previous owner. One of the lads has striped it back to the brick and. It's getting tanked Monday whatever that means

 

[zeebeedee]

Move the pump? Or turn boiler down low?

Pumps not running its only cycling when on gravity hw

 

[Ermintrude]

No move pump so it's fully pumped . I.e right off top of the boiler then tee up for DHW and down and add in a two port or put in a 3 port instead I a tee.

 

[Reg Man]

It should have been converted to fully pumped when that boiler was installed. Shocking that it was not.

 

[IDCHAPPY]

It should have been converted to fully pumped when that boiler was installed. Shocking that it was not.

A property management place I look after with a BBU has the same set up..... Horrible, ancient old things 🙁

 

[Ermintrude]

Bbu love grav DHW. As long as injector elbow and separate conn for rads on opposite side as injector and primary's on same side.

 

[zeebeedee]

What is the difference between a boiler that will operate on gravity fed hw and one that wont? Ive seen switches on some older models that will do both. Hows does it alter the operation of the boiler?

 

[IDCHAPPY]

Bbu love grav DHW. As long as injector elbow and separate conn for rads on opposite side as injector and primary's on same side.

The cylinder bubbles away nicely when the stat gets set about 2 though :lol:

 

[Ermintrude]

What is the difference between a boiler that will operate on gravity fed hw and one that wont? Ive seen switches on some older models that will do both. Hows does it alter the operation of the boiler?

I'm sure iron hex and setting on grav means lower burn . As convection wicks the heat away. Plus block needs to promote grav circulation.