How to tell if I have a primatic cylinder

[LeonR]

Hi all,

Our house was built in the early 70's and we have a Ideal Mexico 2 boiler.

I can't see any 3 way valve on the system and I was wondering how I can tell if the cylinder has a coil in it?

The reason this has come about is because I tried to drain the CH heating system previously , however hot water was coming out of the valve (Heating was off for hours, I know it's the correct valve as it's under the radiator microbore manifold).
I turned off the hot water and then used all of the hot water up so the cylinder refilled with cold water, my theory was that it would cool the coil down (if it has a coil?!) and that did work.

Is it just that the coil in the cylinder uses the same piping as the heating, or does it mean I might have a primatic cylinder?


There are 4 pipes coming out of the boiler, from memory 2 are slightly larger than the others, there is also an electric pump for the heating, header tank, water tank, boiler downstairs and cylinder is upstairs.


Any help would be greatly appreciated!


Happy to post a picture if it helps.

Thanks,
Leon

 

[Best]

If you have a small expansion tank, then it's a conventional open vented system.
You should be able to see a vent pipe which often goes into top of expansion tank and a feed pipe which might connect to the return pipe at coil to hot cylinder
Welcome to the forum

 

[LeonR]

Thanks best!!

Yes the expansion tank is smallish, 1 feed from it and 1 pipe points into the top for expansion.

So is it possible to have a system without an electronic valve which runs heating and hot water on a coil cylinder?

I assume they are not very efficient as they would still be designed this way if not?


Thanks again!

 

[Best]

Yes Leon, it was very standard practice to do boilers in an open vented system and with 2 gravity primaries (often 28mm or old 1") with vent and feed on them solely for the hot water cylinder circuit and 2 pumped pipes for the rads all coming from a 4 connection boiler.
Not allowed nowadays as deemed too slow for heat build up, but was decent if done really well.
Solid fuel boilers are often still done this way and is allowed

 

[LeonR]

Great, thank you for the quick response !! [emoji41]

 

[1Steven]

Was a good boiler in its day

 

[SmokeyJ]

If you have 2 tanks in the loft, 1 big and 1 small then it shouldn't be a primatic cylinder. A primatic cylinder doesn't have a separate tank for the heating.
If you are draining the hot water cylinder through the central heating that would suggest you may have a leak on the coil?

 

[LeonR]

Thanks for the quick replies everybody, I really appreciate it!

I drained it down today so I could add the chemical cleaner, I did it using common sense and various youtube videos.

1.) tied up ball valve (the shutoff valve looked old and like it might just break)
2.) turned off hot water and heating
3.) drained from lowest point drain valve
4.) let air in rads and tightened bleed valve
5.) refilled tank and let it flow through and out the hose for 10 mins
6.) added cleaner to the header tank
7.) bled radiators and let a bit more out the drain valve
8.) switched everything back on

Seems to be working, I was afraid of an airlock when refilling.



SmokeyJ I probably wasn't too clear in how I explained the scenario, I think what was happening was that the CH drain valve shares the same piping as the coil, and if the cylinder has hot water in it then it heats the water that's is in the coil and comes out the same drain valve and burns me, that's why I had to use all the hot water first (to keep the coil cool), at least that's what I think was happening!



That's a picture of the plumbing if anybody is interested, not sure why it's on it's side (two of those pipes join each other above the top shelf).


Thanks for your help everybody!!