Please help me understand the central heating...

Purple-flower

Hello everyone,

I hope someone can help :huh:. Recently the old central heating programmer started behaving erratically (turning itself on and off) and was disconnected by an engineer. We wanted to buy a replacement but were not told which to get...However, we still have hot water (all the time and cannot turn it off, even before the timer was disconnected) but have no heating? Does anyone know how this system works?? And how to make it work efficiently??! Another thing is that every so often, I hear water running through the pipes as if its going to fill the water cylinder? This never used to happen so frequently before.

Set Up
1. Gas boiler
2. Water cylinder upstairs
3. No room thermostats
4. Sunvic 207 CH programmer/timer (disconnected)

Will buying a new timer make the radiators come back on? And would you happen to know why the hot water is always hot regardless of programmer settings?

Thank you so much everyone!

chappers

Can't really answer that question without knowing more about the system, but I expect the answer is basically yes.
The boiler will either provide water to the cylinder or the heating system controlled by the timer via a motorised valve.
Are you sure that there isn't an immersion on the cylinder that is on permanently.
It is also possible that the hot water is by immersion only.
Best ask the engineer who disconnected the old one.

Debbie_Savard

Most CH/HW programmers should fit the bill, Drayton LP522 are commonly fitted.

However, it sounds like your system needs some TLC from a CH technician

>Another thing is that every so often, I hear water running through the pipes as if its going to fill the water cylinder?<

If you really can't turn off the HW it's possible the cylinder is venting very hot water to the expansion tank, then refilling with cold water.

Purple-flower

chappers wrote: »

Can't really answer that question without knowing more about the system, but I expect the answer is basically yes.
The boiler will either provide water to the cylinder or the heating system controlled by the timer via a motorised valve.
Are you sure that there isn't an immersion on the cylinder that is on permanently.
It is also possible that the hot water is by immersion only.
Best ask the engineer who disconnected the old one.

Thank you for your response Chappers. There is a switch on the wall in the cupboard where the cylinder is and I checked it, its off so I am hoping the immersion coil is off... There is a blue box thing connected to one of the pipes leading into the cylinder...could it be responsible at all?

Debbie_Savard wrote: »

Most CH/HW programmers should fit the bill, Drayton LP522 are commonly fitted.

However, it sounds like your system needs some TLC from a CH technician

>Another thing is that every so often, I hear water running through the pipes as if its going to fill the water cylinder?<

If you really can't turn off the HW it's possible the cylinder is venting very hot water to the expansion tank, then refilling with cold water.

Thank you Debbie. I do think its needs to be checked over but I am not sure who to call or what price is reasonable or extortionate for the service. I will check in at Wickes tomorrow for that one hopefully it will fit into our system

southcoastrgi

If it’s blue then it’s most likely made by switch master, they have been bought out by ACL & there is no direct replacement however most programmers should fit although whether the wiring will need altering could be another matter

Le_Kirk

If the programmer was disconnected, it is possible (depends how it was done) that the power to the 3-port valve has been lost and it is unable to move to CH or BOTH and is stuck on WATER. Does it have a manual mode, i.e. a little black lever that you can move to mid-position to check if hot water will flow through the radiators? I am assuming you have a 3-port or diverter valve as you say you have a hot water cylinder and I am assuming that the boiler fires up.

Purple-flower

Thank you so much everyone for your replies. The old programmer was a sunvic 207. I bought a Drayton LP822 today and I'm hoping it will just slot right in the same way...
The blue box is attached to a pipe coming out from the water cylinder. I think you might be right about it being stuck because when I went to have a feel around it for any levers, a black plastic thing dropped into my hand and I'm suspecting that it was a switch of some kind that someone jammed and then it broke off..can it be adjusted with a screwdriver?

Le_Kirk

I think the "black plastic thing" is the manual lever, so no it can't be adjusted with a screwdriver.

Purple-flower

Le_Kirk wrote: »

I think the "black plastic thing" is the manual lever, so no it can't be adjusted with a screwdriver.

Does this mean the whole unit will have to be replaced in order to regain control of the hot water?


I purchased a Drayton LP822 programmer today, do I need a plumber or electrician to fit it? Any ideas how much is a good price for the north London area

Le_Kirk

Purple-flower wrote: »

Does this mean the whole unit will have to be replaced in order to regain control of the hot water?

If it is the same as mine, you can purchase just the actuator and can change it without having to remove the valve itself, so saving you having to drain down the system. You will have to gain access to the electrical connections so if you are not competent and confident, I suggest employing a professional. Can you see the part number on the valve anywhere? If it is a Drayton could be something like MA1, ZA6, ZA3.

Purple-flower

Le_Kirk wrote: »

If it is the same as mine, you can purchase just the actuator and can change it without having to remove the valve itself, so saving you having to drain down the system. You will have to gain access to the electrical connections so if you are not competent and confident, I suggest employing a professional. Can you see the part number on the valve anywhere? If it is a Drayton could be something like MA1, ZA6, ZA3.

There are two boxes on two separate pipes, one says "actuator" which is handy the other is angled toward the cylinder so it's difficult to make out what is on it. Are they both actuators?