basic central heating system

[mrcrow]

i have just moved into a 1960's bungalow. the central heating is pretty basic as i see it but effective..here is some data

Potterton kingfisher boiler CF60 CAT 1N
AMFVenner dial timer and manual control switching giving hot water and heating, timed/off/constant
No indirect cylinder thermostat to control hot water temperature
Hot water temp controlled by setting boiler thermostat to low
When central heating is required the hot water must be on as well for similar timings
All radiators except bathroom have thermostatic valves
With the gravity hot water system on the radiators will also heat up if the valves are set to high numbers, and the bathroom always.
Spare tappings on boiler heat exchanger not used.

i am quite happy at present with the performance but see that some upgrading might be advantageous..
adding a cylinder thermostat and renewing the controls...but keeping the simplicity of the pipework

grateful for any comments and advice

yours
mrcrow

 

[ChrisR]

You wouldn't JUST add a cylinder stat, because if the CH were on, the HW would get hot regardless. You could put a motorised valve in the cyl return, to stop the gravity circulation. That is C plan (See Honeywell's web site). That does NOT satisfy current building regulations because it isn't a fully pumped system.

Couple of things wrong with the drawing - don't put a valve in the feed pipe, and you seem to have the cylinder return going off to the rads! Better take it to the boiler..

If you don't want to do the job properly(!) and make it fully pumped in normal S or Y plan configuration (See Honeywell's web site) because the pipe changes are too hard for you, you could add a second pump, just to supply the cylinder. On the cyl return not the flow, so the route to the vent is inimpeded.
You could put a pipe stat on the cylinder primary flow, then wire the cyl stat and programmer to it such that the cylinder's pump comes on

IF Programmer calling AND Cylinder cool AND Flow pipe hot.

(flow pipe gets hot by gravity)

The introduction of a pump (normal CH type 15-50 on low) seems to be enough resistance that gravity heating of the HW more or less stops, but you could of course put a motorised valve in the return if you prefer to. If you do that you would use its switch to control the boiler so you wouldn't need the pipe stat.

You may find that the new pump makes water come out of the vent if you leave feed and vent where they were. solutions are to make the vent pipe go higher before it comes down to the F & E tank, or move the feed across to where the vent connects - effectively making a "combined feed and vent". System would be slower to fill if you did that, but it works.

Hope I haven't been too confusing ?

 

[kevplumb]

chris either my eyes are going or the flow goes thro the cylinder then supplies the heating if you put a valve in the return the heating goes off with the water

weird system

 

[ChrisR]

yes I assume that bit must be wrong - the heating flow is missing I think - and the returns don't go together to the boiler.

 

[kevplumb]

mcrow wrote
Spare tappings on boiler heat exchanger not used.
would seem to suggest the drawing is right
come across some oddballs never seen one like that

 

[mrcrow]

mcrow wrote
Spare tappings on boiler heat exchanger not used.
would seem to suggest the drawing is right
come across some oddballs never seen one like that

thanks all...comments on wierd seem to correspond with mine...
the indirect coil outlet (bottom) actually does feed the radiators via 40mm pipes that go across the loft and drop down at two places to the lounge and second bedroom...so that i have a gravity rad system/or pumped.
the comment about the cylinder stat is good..i forgot about the central heating part of would mean having to be ever changeing for each..as i do now but at the boiler stat..
i can live with this as it is..wierd as it is..and we are getting used to having the bathroom rad a bit warm during the day..keeps the towel dry..
ps
i have checked the drawing again and it seems to be 'as is' piped..chrisR as you comment..
'Couple of things wrong with the drawing - don't put a valve in the feed pipe, and you seem to have the cylinder return going off to the rads! Better take it to the boiler.. '
..as an after thought...there was an immersion heater in the old indirect cylinder they tell me..but when a new one was put in they didnt put in an immerser..
seems to me they may have used the whole system just for central heating primarily with the hot water as a bonus and the immerser for summer water heating...
fait accompli as the say in france...
regards to you all for very good comments...
mrcrow
.....
just had another romp amongst the black and dirty yellow loft insulations...no down pipe to boiler from indirect...
and the feeders to the rads are 22mm off of a 30mm tapping off of the cylinder...
just lagged the header tank for the gravity water system and the galvanised tank being used for the boiler header is lagged in wicked fibreglass and old carpet...
the pipes are nearly all lagged in hessian and bestowed with swathes of glass fibre...
back to b and q for miles of pipe insulation and another tank insulation pack..
cheers
mrcrow

 

[mrcrow]

i need to control my hot water temp now since i am running the central heating on each day..and the boiler is set a bit higher...
here is a diagram of the present set up regarding piping etc.
as you may see the cylinder coil also feeds the radiators in series
can you suggest a simple way that i can keep the h.w. temp lower than the cen heat temp/boiler temp.
yours
mrcrow

hope this img loads ok..new website.

 

[kevplumb]

bypass on the cylinder and a zone valve and stat
stat on cylinder and the valve after the bypass

 

[mrcrow]

bypass on the cylinder and a zone valve and stat
stat on cylinder and the valve after the bypass

thanks...sort of thought it might be that simple...didnt want any extra boiler controls
the power for the zone valve just needs an on off switch?
or should i go over to the elec section for that.
another improvement on this oldie bungie..

 

[kevplumb]

switch the valve thro the cyl stat and you control the temp
sorry mis read your post yes you need power but it must come from the boiler isolater so it kills everything

 

[mrcrow]

i have just moved into a 1960's bungalow. the central heating is pretty basic as i see it but effective..here is some data

Potterton kingfisher boiler CF60 CAT 1N
AMFVenner dial timer and manual control switching giving hot water and heating, timed/off/constant
No indirect cylinder thermostat to control hot water temperature
Hot water temp controlled by setting boiler thermostat to low
When central heating is required the hot water must be on as well for similar timings
All radiators except bathroom have thermostatic valves
With the gravity hot water system on the radiators will also heat up if the valves are set to high numbers, and the bathroom always.
Spare tappings on boiler heat exchanger not used.

i am quite happy at present with the performance but see that some upgrading might be advantageous..
adding a cylinder thermostat and renewing the controls...but keeping the simplicity of the pipework

grateful for any comments and advice

yours
mrcrow

to cut a long and old story short i finally got british gas to do a new boiler and upgrade...being a retiree i got good discounts
thanks for all the support
geof

 

[Whitespirit66]

I've been waiting for 5 years to find out how you resolved the situation.

Now I find that you have thrown your lot in with the devil , and given BG your retirement savings!!!