What old CH layout is this? Remote TRV on HW cylinder?

[jase_31]

Hi,

Can anyone help me work what the following system is called (Y / W C Plan etc)

Fully pumped, but with no 3 way (or come to that any valves at all).

The HW cylinder is fitted with what looks like a TRV with a remote probe to the cylinder.

The timer is an old danfoss 103, with option for constant or timed.

If my understanding is right, it appears that cannot have water without heating, which is even worse than with a gravity HW system. Am I missing something.

If Rads are fitted with TRV then the system could be used to heat water, however when the HW reaches temp the boiler will cycle?

Is it possible to put a room stat on? I dont think so, as if the room stat is not calling for heat there is no HW?

 

[Ray Stafford]

Did the thing that looked like a TRV look like this or like this ?

 

[jase_31]

Did the thing that looked like a TRV look like this or like this ?

Yes. Same as the one below. But only in a 2 port fitted inline to top of heating coil. A manual bypass is also fitted for when the valve is closed.

BSS Havelock - 013U808700 15MM RAVI/KOVM 3 PORT VALVE - Danfoss Randall - Differential Pressure Regulator Valves

 

[Ray Stafford]

I'm not sure that the system design had a name. I just called them all "tapstats" because mostly round here they were Draytons, and thats what Drayton called them.

And I think you are right - IIRC they were really designed to stop the cylinder from getting too hot, rather than calling for heat themselves. But to be honest, its a long time since I saw one.

 

[jtsplumbing]

It will be a Drayton or Honeywell tap stat, in summer you have to turn off all the rads, unless some one has fitted a valve (Gate) to shut off system, best to upgrade system with a control pack.

 

[jase_31]

I have to admit that I have not seen one before. Think they might have been dated from around the early 80s. Problem with the system is (unless I am missing something) is that is cannot do HW only, and there is no interlock when the trv closes.

Can a room stat be added? I am thinking that the layout should be updated to Y plan?

 

[jtsplumbing]

There is loads of these systems around, no control on system, just buy a control pack it has every thing in it to upgrade you can have a 3 port pack or one with 2 valves, if you do your own wireing is easey to fit .

 

[Roger Welton]

There is a place local to me that has one of these fitted to a 65kW kingfisher, the only control they have at present is a single chanel timer (no trv's either) it's all geting replaced at the end of the heating season, I expect there gas bill next year to be a revalation.

 

[stevetheplumber]

be carefull jase as the cylinder can be teed in anywhere on these systems to fit a y plan you often have to run a new return back to boiler also check if the feed and vent are where your going to need them is there a ball valve in the f& e tank servowarm loved these sytems and rarely put in a ballvalve and therefore no overflow