Please Help..... No hot water with central Heating on..... And no 2/3 port zone valves anywhere??

[david baldrey]

Hi,

I have just moved into a new property in which we have a system boiler (fairly new ideal unit). The boiler is located under the stairs and coming from the boiler is 2 pipes (F&R) with a grundfos pump. the two pipes rise up into the floor void above and out of site. the cylinder is in the main bedroom airing cupboard which is the opposite side of the house. there is no 2/3 port valves anywhere and the cylinder features a manual TRV type control. we have only just moved in and it appears the only way to heat the cylinder is to enable the central heating from the room stat! surely this cant be right?

Please help!

 

[ianmcd]

Not sure what you mean can you post some pics of what you are calling a manuall TRV type control

 

[gasmanstu72]

you probably mean a tapstat
one like this?

if so, it could be stuck, they work the same as a normal TRV, so unscrew the head and see if the pin moves up and down, if not try to free it up with a pair of pliers, or give it a whack with something

 

[david baldrey]

Thanks for the replies..... the manual TRV type control is linked to an external cylinder probe. No issue with the TRV as it works and we get plenty of hot water..... but only when the heating is on..... there is no 2 or 3 port motorized valve anywhere!?! so in summer are we going to have to have the heating on to get hot water?

 

[david baldrey]

Essentially what i think i have is a single (primary) heating circuit, TRVs on the rads and a tap stat on the cylinder. is there any way i can get the boiler to heat up the cylinder without the heating? if so what sort of work is involved? thanks again

 

[JohnD]

It's quite likely that you have Gravity (convection) flow to the cylinder.

This is commonly found on old systems. The pipe between the cylinder and the boiler may be 28mm not the more common 22mm.

You need to post photos of your programmer, room stat, pump, and the pipes around the boiler and the cylinder, and of the valve you mention on the cylinder pipe.

You must not cut or kink the "wire" attached to the cylinder valve. It is in fact a capillary pipe and cannot be repaired. When I had one, IIRC a new Tapstat was over £100, and very difficult to find.

 

[david baldrey]

Yes the cylinder is gravity fed, and looks like a 28mm pipe into the cylinder. the issue is the boiler and cylinder are at polar opposite ends of the house and on different floors. ill see if i can get some pics up in a moment

 

[david baldrey]

 

[JohnD]

you may want to consider converting it to fully pumped. I did mine, with assistance on here. I got some improvement in HW economy when I insulated the gravity pipes.

My tip is to add a system filter and give it a chemical clean before you start, because a lot of old sediment is likely to be disturbed when you start work, and a lot more once the pump runs. Summer is the best time to work on heating systems.

 

[david baldrey]

Thanks John...... how involved is that, are we talking ripping up floors, ceilings etc? and cost?

 

[JohnD]

In my case, the most arduous work was taking up all the floorboards between the boiler and the cylinder to run a new cable for a cylinder stat. I insulated the pipes as I went. That's an uncomplicated DIY job. A friend who is an HVAC engineer drew up the circuit diagram and helped me fit the pump and valve in an afternoon. You might want to get a plumber to do that for you.

The parts cost a few hundred. I did the chemical clean and fitted the filter myself in advance, not difficult if there is room to work and you can do basic plumbing, and it is quite satisfying to see the grime of ages coming out.

 

[david baldrey]

the cable between the two may not be an issue. i have a route up into the loft in both locations. so essentially the pipework can remain as existing between the boiler and cylinder? what parts would i need (don't need an itinerary just a general list)?

That's brill. better than my initial thoughts that the whole system needed replacing and new pipework everywhere. especially as we just had virtually the whole place plastered!

 

[JohnD]

cylinder stat
wiring centre
timer/programmer
3-port valve (can also be done using a 2-port. 28mm valves are more expensive than 22mm)
System filter (I used one of the early Magnacleans. Very fast at collecting black sludge, but prone to leaks. I now have a Spirovent made of brass)
cables and clips
foam pipe lagging
If times are hard you may be able to get a modern programmer on ebay or somewhere, from somebody who has converted to a combi.
Honeywell is a very good maker .
Sentinel X400 cleaner
X100 inhibitor, for when you've finished the changes
X200 if you are in a hard-water area



I don't like wireless controls because they give extra opportunities for failure

If you are going to use a heating engineer, let him choose and supply the components or he may grumble about your choice. Personal recommendation is best

 

[david baldrey]

Thanks John, i will start a shopping list

So would the 2/3 port MV go in next to the cylinder in place of the tap stat? then a cable from this MV back to the wiring center that would go adjacent to the boiler under the stairs

 

[gasmanstu72]

your system is already fully pumped (in a roundabout way) the pump is on the return in this case.
what you have is a KOVM valve.
i've not seen many at all, and the one's i have seen i've removed and replaced with motorised valves. which you would be best to do in this case i think.
you might be able to fit the pump and valves down by the boiler if you can get a pipe from the loft down to that location.

someone should be able to tell you exactly how those KOVM valves work,