A few (basic!) Heating/Immersion questions..

Pauley2

I noticed a puddle in the boiler shed the other day. Looked at the 3bar pressure release valve and it was dripping. The gauge on the (gas) boiler was up at 3 bar so that made sense. I then checked the expansion vessel - it felt "solid" (like a melon), so I presume that the bladder gave away, wore out or something and decided to replace it. (I first tried pushing the valve open and got nothing - no air or water. Then I tried pumping it up but it wouldn't take ANY air - even when I opened a bleed valve to allow room to expand. Later when I had it removed and drained it still wouldn't take any air, so something wrong with the valve anyway..).

Q1. The old one, a "Reflex" from about 2004, was a red 12litre one with a label that said "3bar - 393K". What does the "3bar" on this mean? - is that the max operating pressure or the pressure it should be inflated/topped up to before installing? (the supplier said it should be factory filled with air, but that there's no harm checking before installing).

Q2. Having had a leak I thought it best to add more inhibitor. I noticed all the bottles say "Not for Use in Single Feed Indirect Cylinders". Why? - Isn't that the most common configuration? - If so, what should I use? (the supplier said that "everybody uses that - it should be OK")

Q3. Once it's up and running, what should the normal operating pressure get to? (it's gravity feed from the attic cold water tank, but closed loop insofar as there's a one-way valve (2 in series actually) in the feed (which I was told to leave on all the time).

Q4. Also, because its gravity feed, I presume I'll never get above .8 bar or so when it's cold?

Q5. With the boiler based HW/CH now unavailable I turned on the immersion for the first time in probably years. It boiled like mad. I removed the thermostat from the cylinder and saw that it was completely corroded. Anyway, I went looking for a similar replacement ("standard 11" I believe) but after trying 4 places I cannot find one that (like the old one) has a built-in resettable safety pop up cut out in addition to the standard temp setting. I'll go with the non-cut out if I have to, but do they really not make ones with a safety cut out anymore? (looking in Northside Dublin..) - and BTW the irony is not lost on me that the cut out failed in the old one, but still...

Tx for any help...

sullzz

Pauley2 wrote: »

I noticed a puddle in the boiler shed the other day. Looked at the 3bar pressure release valve and it was dripping. The gauge on the (gas) boiler was up at 3 bar so that made sense. I then checked the expansion vessel - it felt "solid" (like a melon), so I presume that the bladder gave away, wore out or something and decided to replace it. (I first tried pushing the valve open and got nothing - no air or water. Then I tried pumping it up but it wouldn't take ANY air - even when I opened a bleed valve to allow room to expand. Later when I had it removed and drained it still wouldn't take any air, so something wrong with the valve anyway..).

Q1. The old one, a "Reflex" from about 2004, was a red 12litre one with a label that said "3bar - 393K". What does the "3bar" on this mean? - is that the max operating pressure or the pressure it should be inflated/topped up to before installing? (the supplier said it should be factory filled with air, but that there's no harm checking before installing).

Q2. Having had a leak I thought it best to add more inhibitor. I noticed all the bottles say "Not for Use in Single Feed Indirect Cylinders". Why? - Isn't that the most common configuration? - If so, what should I use? (the supplier said that "everybody uses that - it should be OK")

Q3. Once it's up and running, what should the normal operating pressure get to? (it's gravity feed from the attic cold water tank, but closed loop insofar as there's a one-way valve (2 in series actually) in the feed (which I was told to leave on all the time).

Q4. Also, because its gravity feed, I presume I'll never get above .8 bar or so when it's cold?

Q5. With the boiler based HW/CH now unavailable I turned on the immersion for the first time in probably years. It boiled like mad. I removed the thermostat from the cylinder and saw that it was completely corroded. Anyway, I went looking for a similar replacement ("standard 11" I believe) but after trying 4 places I cannot find one that (like the old one) has a built-in resettable safety pop up cut out in addition to the standard temp not. I'll go with the non-cut out if I have to, but do they really not make ones with a safety cut out anymore? (looking in Northside Dublin..) - and BTW the irony is not lost on me that the cut out failed in the old one, but still...

Tx for any help...

Not much to say other than you are over thinking absolutely everything!! So from the bottom up ,

5. if something trips its for a reason, why be able to reset it without knowledge?

4. Nope not if it builds in pressure when heating with a failed expansion vessel and a nrv and cools, where does the excess pressure go once it drops below 3 bar?

3. Usually 2 bar once the expansion vessel is ok.

2. I find fernox best to use.

1. Expansion vessel should be ideally charged to 1-1.5 bar

Pauley2

Thanks... Just being cautious..

Re the warning about not using Inhibitor on Single Feed Indirect cylinders. I since found out that this refers to a type of cylinder more popular in the late '70's where both HW and CH water were heated in the same cylinder but separated internally only by an air "bubble". If that bubble ever disappeared for whatever reason, your CH water would mix with your tap water!

Re the immersion cut out. The old one is a "CoTherm". The point of the cut out is, should the thermostat fail, to prevent the water boiling uncontrollably and spitting scalding hot water out of the taps. I've seen this happen. Belt and braces, so to speak and in my case it still failed, but I'd still like to find a like replacement..

Cheers...