New timer - Gravity indirect HW, pumped CH, no thermostats

[ripe]

Hi all,

I saw from this thread in Nov 2004 that Part L building regs at that time require both room stat and cylinder stat:
//www.diynot.com/forums/viewtopic.php?t=16134

Our situation has an old Thorn boiler which continues running reliably, but the only temperature control is the boiler's control knob (and the TRVs). It has gravity-fed HW (indirect cylinder), and the pumped CH has a 2-port valve, and most of the rads have TRVs. There is no room stat, and no cylinder stat.

There is an electromechanical timer which has two ON tags, and two OFF tags which cycle on/off/on/off as the 24hr dial rotates through the day. It also has a selector switch (HW only / HW+CH) - there might also be an OFF position, but I'm not sure now.

We need to replace the old timer (tenants accidentally broke it when trying to change the timing of the ON and OFF tags), and now the dial doesn't rotate at all. We need to minimise disruption to the tenants (shift workers), and cost to the landlord. The room stat would be easy enough to add near the boiler, but adding a cylinder stat would require a tricky cable run.

Q1 - If we simply replace the timer, do we really need to upgrade the rest of the system (because that could trigger replacing/adding much more than just the timer and stats)?

Q2 - I cannot find any circuit diagrams that seem to apply to this situation - can someone help please?

Many thanks!

 

[ericmark]

As to cylinder thermostat you can get radio controller and I did this for my fathers central heating as without the hot water is same temperature as central heating water and could scold anyone using it.

As to thermostats you do have them as far as I am reading with TRV fitted.

There is a problem with no thermostat on old boiler as it will keep cycling to check temperature but with newer boilers an anti-cycle software is normally included. Also TRV are suited to the modern boiler which gives a variable output according to the temperature of the returning water and any thermostat is only to switch off the system in the summer. But with older systems the thermostat is the main control.

I have an old boiler and I have used a modern thermostat which includes a timer and this controls my open plan down stairs very well and TRV are only used in bedrooms to stop them over heating if a door is left open.

However my dads house has normal rooms and hall arrangement and with a thermostat in the hall the control is very poor.

So much depends on the design of the house and there is no one size fits all.

However I would look at these which very well combine time and thermostat control including frost stat as they don't turn off as such but just change the control temperature.

 

[ripe]

Thanks Eric (and/or Mark) - very helpful!

You wrote: "I have an old boiler ..." - well I do too, and she's always feeling the cold!

I have seen something similar to that thermostat/timer at B&Q, and will have a look for wireless cylinder stats.

Q3: Is there a wireless system for BOTH cylinder and room stats?

Q4: You mentioned "anti-cycle software" - is that in the boiler? Or in the programmer? It's something I would love to have for my own home's system. I am familar with boilers with PCBs but not with onboard computers to run software. Or have I misunderstood you?