Indirect cylinder used solely as an immersion heater

[TerryWaite]

Hi

went out to do a cylinder swap to exchange an indirect cylinder that was leaking from the body, more or less a straight swap, slight pipework mods.

On questioning customer, I found the guy had no boiler or heat source for the indirect coil, he had storage heaters for his heating, and the two pipes coming off his indirect coil out of the cylinder went straight up and both terminated like open vents above the f and e tank.

I was going to just cut these out and cap the indirect connections off on the new cylinder (more scrap for me, or the mrs, as she now deals with the scrap) but was slightly reluctant as I thought this must have been done for a reason, so to cover myself I just reconnected them the same way.

Would the heated hot water in the vessel cause the air to pressurise in the coil, to a dangerous presure? Is this a common thing?

Can you get cylinders with just an immersion heater in and no coil?

And also, the cylinder was 900 high, I bought a 23 or 27 " immersion heater but it would not screw in as it was catching on the coil inside. Anyone ever had this problem? I had to go out and get the next size down I think this was a 14" or something, same kilowattage like (3kw) but I am worried that this will only heat the top portion of the cylinder up and maybe the cust. will get a little bit of steaming hot water rather than lots water at the required temp. There was no cylinder stat fitted to old one so I havent fitted on on new one. Immersion heater dial was set to middle and sealed with a spot of gunk. it came like this I assume so as not to be tampered with.

Did I do the right thing?

regards

John

 

[jtsplumbing]

Yes you want a Direct cylinder, 27" will fit in with a bit of fiddleing about, 14 " will not give full tank of water, used to fit indirect cylinder as it was cheeper than direct (Strange but true)

 

[PlumbBobBob]

yes you can get a direct cylinder without a coil

beat me lol

 

[stevetheplumber]

if the imersion fouls the coil i usually give the coil a little shove over with a bit of 2x2 timber through the imersion boss the fourteen inch one will only heat the top third of the cylinder not enough to fill a bath you can just leave the coil connectors with the plastic caps on to stop mice spiders and cockroaches getting a warm home

 

[tamz]

The existing cylinder may have been a primatic and that was someones idea of blanking it off rather than capping it (not that capping it would have made any difference on a primatic). Take a grinder to it and have a look.

If the immersion is catching the coil screw a 2 1/4" plug in a few turns and bend the tapping a bit straighter then fit the immersion. A 14" is too small for a 36" cylinder.

 

[Guest123]

Ah, the old Primatics, if the bubble went, they were a nightmare.

 

[TerryWaite]

thanks alot, i may have to go round and replace the immersion then, i shall see whether custard complains or not, he said he doesnt use the bath he has an electric shower. But ill be ready for the callanyhow.

Why on earth do they not angle the tapping on the top so that it goes down the middle? seems ludicrous to me! And where would you get a 2 1/4" plug? I thought BSPT pipe thread sizes were 2" and then 2 1/2"??

If you left the indirect coil with the plastic caps on, if the annulus burst inside, would you not flood the house?

regards

John

 

[desrob]

thanks alot, i may have to go round and replace the immersion then, i shall see whether custard complains or not, he said he doesnt use the bath he has an electric shower. But ill be ready for the callanyhow.

Why on earth do they not angle the tapping on the top so that it goes down the middle? seems ludicrous to me! And where would you get a 2 1/4" plug? I thought BSPT pipe thread sizes were 2" and then 2 1/2"??

If you left the indirect coil with the plastic caps on, if the annulus burst inside, would you not flood the house?

regards

John

terry had you never came across a direct cylinder before,i struggle with understanding electrics,but then again i am a plumber,the basics are there..?

 

[tamz]

And where would you get a 2 1/4" plug? I thought BSPT pipe thread sizes were 2" and then 2 1/2"??

2 1/4" is the size of a std immersion thread. You can buy plugs anywhere.

 

[Gray0689]

thanks alot, i may have to go round and replace the immersion then, i shall see whether custard complains or not, he said he doesnt use the bath he has an electric shower. But ill be ready for the callanyhow.

Why on earth do they not angle the tapping on the top so that it goes down the middle? seems ludicrous to me! And where would you get a 2 1/4" plug? I thought BSPT pipe thread sizes were 2" and then 2 1/2"??

If you left the indirect coil with the plastic caps on, if the annulus burst inside, would you not flood the house?

regards

John

Have you been plumbing long mate?

 

[stevetheplumber]

more chance of the cylinder bursting than the coil and what\ about all the other piupework that could burst

 

[TerryWaite]

Have you been plumbing long mate?

I am an industrial commercial pipefitter by trade, I am ok at domestic plumbing and have my domestic gas safe, but housebashing is not my background, hence why I come on here, theres some great people on here whom most of them give sound advice.

 

[TerryWaite]

more chance of the cylinder bursting than the coil and what\ about all the other piupework that could burst

I know what youre saying but would you not atleast put two proper caps on it atleast?

 

[Mike Jackson]

No need at all. The coil is a lot stronger than the rest of the cylinder as they are designed to work at 3 bar on sealed systems.

 

[TerryWaite]

thank you

 

[Dannypipe]

A 14" immersion isn't going to give him much hot water.

Not top fixed anyway. On some cylinders you get a 14" in the side (top and bottom) and the result is a tank full of water. The basic rule is animmersion will only heat water to the same length. It won't heat water below. So the majority of your clients cylinder is going to be unheated.

 

[TerryWaite]

Thank you Danny, as stated I did originally have a 27", I dont know why the tapping isnt angled in the first place, seems stupid to me. I will try to bend the tapping and change the immersion.

I see what you mean a 14" top entry immersion is only gonna heat top third of tank. Do you mean you have 1 14" in the top and another one in the bottom of some cylinders?

 

[Dannypipe]

Kind of. They are side entry and one is in the bottom (a few inches up) and another one in the top third. (For a booster supply).

You mainly see this on unvented cylinders and thermal stores. More often they'll use an 11" immersion, but I know a Gledhill that uses a 14".

I've also come across it on conventional vented cylinders. You can also get side entry 14" immersion heaters that are over 3KW (but it's rare) I've got one client who's got a bloody great big house with two cylinders. One of them has a 6KW 14" side entry immersion.

I know this is all besides the point but once I start rambling I tend to get carried away. A few years back, one of these cylinders in the clients house sprung a leak and I had to change it. Was a good day for scrap....but back then wasn't as valuable as it is today.