Gravity Hot water ???

[jaw]

Hi

Its now 11:05pm and I can't see the wood for the trees!

I have visited a customer today who wants to replace their old Ideal E type RS 50 with a more modern and efficient floor standing boiler on a fully pumped Y plan system (Obviously avoiding the possibilty of "pumping over"). The current system from what I can see is gravity HW and pumped CH. Thinking about it tonight, what I can't get me head around is the following:

The property is a bungalow. The boiler is in the garage and the existing HW (gravity?) flow pipe rises from the boiler into the loft space. It then travels horizontally before dropping down to the top connection of the hot water cylinder in the bathroom. The return pipe to the boiler is then visa versa from the bottom connection of the cylinder. How can gravity work in this situation when the pipes in effect go up, across and down in both directions? Or am I being totally thick !

My answer would be to convert the current system to a sealed system but am looking at all avenues at the moment

Any ideas welcome, Thanks

 

[SimonG]

If it's working then it's inefficient. My choice would be S plan. Old system? I'd be doing a pressure test before sealing the system.

 

[SafeGasInstall]

Are you sure is gravity ? As I can not see water going up then horizontal run then drop down then he cylinder and come back up then horizontal run ten drop down to boiler ! I am not saying you are wrong but just me have difficult understanding phisichs this time if the day .
Is there 4 pipe coming out of boiler ? comvert to fully pumped open vent and install y or S plan . Remove primary flow and return , cut out old cold feed and exp pipe as much as you can and renew all pipe work ! Must pf central heating too

 

[Chalked]

A lot of 1970's bungalows were done on gravity this way. It does work.

 

[SafeGasInstall]

A lot of 1970's bungalows were done on gravity this way. It does work.

Thank you for clearing this out ! I have never seen one yet ! But I am prepared now !

 

[Chalked]

Are you sure the cylinder return doesn't go down Ito the floor? ( just read your post properly)

 

[jaw]

Are you sure the cylinder return doesn't go down Ito the floor? ( just read your post properly)

I dont believe it does as a room stat operates the pump for the CH side

 

[jaw]

Must pf central heating too

Thanks SafeGasInstall. What do you mean by the above in your reply?

 

[Chalked]

Thanks SafeGasInstall. What do you mean by the above in your reply?

Power flush .

 

[jaw]

Indeed. PF could have stood for a few things

 

[Best]

The gravity flow & return pipes both going up into the loft & dropping to cylinder coil will work no problem as long as they have vent/feed pipes & rise from boiler to these. Also, the cylinder needs to be high enough as usual, obviously.
Think about it, - as the flow water rises when the boiler heats it, the return water replaces it. Not ideal though, but needs must sometimes. Just the same if you dropped pipes off these primaries to a heat leak rad, - if the rad is high enough it will work well. Only gravity on solid fuel nowadays & needs the flow & return in a nice loop, flow up, return down to be correct.

 

[Gray0689]

Hi

Its now 11:05pm and I can't see the wood for the trees!

I have visited a customer today who wants to replace their old Ideal E type RS 50 with a more modern and efficient floor standing boiler on a fully pumped Y plan system (Obviously avoiding the possibilty of "pumping over"). The current system from what I can see is gravity HW and pumped CH. Thinking about it tonight, what I can't get me head around is the following:

The property is a bungalow. The boiler is in the garage and the existing HW (gravity?) flow pipe rises from the boiler into the loft space. It then travels horizontally before dropping down to the top connection of the hot water cylinder in the bathroom. The return pipe to the boiler is then visa versa from the bottom connection of the cylinder. How can gravity work in this situation when the pipes in effect go up, across and down in both directions? Or am I being totally thick !

My answer would be to convert the current system to a sealed system but am looking at all avenues at the moment

Any ideas welcome, Thanks

Gravity can't work must be pumped somewhere