Gravity Hot Water

[carlosfandango]

Is it ok to have gravity hot water on new boiler due to a back boiler being linked to system?

 

[Last Plumber]

NO DEFINITELY NOT.

I presume you mean new condensing boiler.

 

[SimonG]

Is it ok to have gravity hot water on new boiler due to a back boiler being linked to system?

Bit more info as to what you have.

 

[Chriswareham]

if you are fitting new boiler then the pipe work will be converted to a fully pumped system the cylinder will heat up farster and you will have better control over the hot water temperature
i think this is the answer to your q in a round about way?
my be i got the q wrong? how knows!

 

[Chriswareham]

if you are fitting new boiler then the pipe work will be converted to a fully pumped system the cylinder will heat up farster and you will have better control over the hot water temperature
i think this is the answer to your q in a round about way?
my be i got the q wrong? how knows!

 

[carlosfandango]

Bit more info as to what you have.

The system is the twin coil cylinder is right next to boiler the pump for the CH is Tee'd off the back boiler and boiler flow in loft so when back boiler heats water pump kicks in to rads.

I have put a separate pump on the flow for HW but am getting water spewing into expansion tank when it is water only.

 

[Best]

The system is the twin coil cylinder is right next to boiler the pump for the CH is Tee'd off the back boiler and boiler flow in loft so when back boiler heats water pump kicks in to rads.

I have put a separate pump on the flow for HW but am getting water spewing into expansion tank when it is water only.

You are not explaining properly what sort of system you have.
You say it has a twin coil cylinder, - so what does that mean? Do you have a back boiler and some sort of other boiler elsewhere both linked to your heating system?
You definitely shouldn't fit a circulating pump onto gravity pipes from any boiler.

 

[carlosfandango]

You are not explaining properly what sort of system you have.
You say it has a twin coil cylinder, - so what does that mean? Do you have a back boiler and some sort of other boiler elsewhere both linked to your heating system?
You definitely shouldn't fit a circulating pump onto gravity pipes from any boiler.

OK I will try better what the old system was was a oil boiler with the cylinder next to it with gravity hot water the cylinder is twin coil with one side heated from a back boiler from fire the other side gravity from boiler the pump for the central heating is in the loft after the flow of back boiler that pulls from oil boiler and back boiler when water up to temp I assume I can't move this pump.

Now there is a condensing boiler there and I am trying to get it fully pumped as S plan but am getting water into expansion tank when it is just water on clock

 

[Best]

There should never have been only one pump serving radiators circuit from 2 boilers. So that was something the installer who did the new condensing boiler should have investigated.
If you are not a heating installer, or having no experience on link up dual heating systems, then you are better getting your boiler installer back to sort it, or maybe best a more knowledgable heating person. No condensing boiler is suitable for gravity hot water and it also is against regs.
A dual heating system, like what you describe, can be designed without gravity pipes from oil boiler

 

[Chriswareham]

i am sorry mate but you have compleatey lost me you are saying you have a new condening boiler in the loft and a back boiler that sill heats the hot water on the second coil does this have its own header tank? if you have a new condening boiler that does the outher coil and centrol heating doses this have a header tank or is it a seadled system

 

[Best]

i am sorry mate but you have compleatey lost me you are saying you have a new condening boiler in the loft and a back boiler that sill heats the hot water on the second coil does this have its own header tank? if you have a new condening boiler that does the outher coil and centrol heating doses this have a header tank or is it a seadled system

I am also confused, but I can only guess the system is still all open with gravity hot water to both coils somehow. New gas or oil boiler, with an original back boiler I presume. If that's right, then somebody has made a botch

 

[king of pipes]

This system does not meet the current building regulations dont mess with it get a heating specialist in to sort it out combining systems with more than one heat source is not always possible and can be dangerous without saftey controls are not put inplace .

 

[SimonG]

Who installed the condensing, oil I presume, boiler?

 

[Best]

Has to have been a diy swap by the sounds of it.