losing pressure in central heating

sunnyday1234

Hi guys

I have OFCH and every few weeks the rads in my converted attic are only half hot. I look at the pressure and its very low so i just increase pressure, bleed rads in attic (there is air present), increase pressure then again to 1.5 and away i go.

is this normal with a converted attic ? i know air rises to the top but is every few weeks a bit much ? I dont see any noticable leak anywhere

thanks for any advice

van_beano

sunnyday1234 wrote: »

Hi guys

I have OFCH and every few weeks the rads in my converted attic are only half hot. I look at the pressure and its very low so i just increase pressure, bleed rads in attic (there is air present), increase pressure then again to 1.5 and away i go.

is this normal with a converted attic ? i know air rises to the top but is every few weeks a bit much ? I dont see any noticable leak anywhere

thanks for any advice

I've the same issue myself albeit I've got a gas boiler. Pressure reduces from about 1.2 to under 1 every 3 weeks or so, at this level the bleeding of rads isn't necessary but if I left it the pressure would reduce further and the rads would need to be bled.

From my understanding is that there's a tiny leak somewhere in the pipe work of the house. Water escapes, air gets in and this air will usually lodge in the rads at the highest point in the house, attic in your case.

Topping up the pressure isn't a big job but I'm just concerned about the long time effects of adding fresh water to the closed system every 3 weeks, could this lead to corrosion in the pipes eventually? Finding the leak could be a difficult task unless it's noticeable by a puddle under skirting or something. Please be advised that I'm no expert and I'm as far from being a plumber as I am an astronaut, just going from personal experience.

roy rodgers

There probably is a slight leak within the system some where.
It be no harm to add a bottle of leak sealer to the system this should solve any problems.

sunnyday1234

roy rodgers wrote: »

There probably is a slight leak within the system some where.
It be no harm to add a bottle of leak sealer to the system this should solve any problems.

thanks guys. How would i add the leak sealer ? where would i add it ?

sunnyday1234

after increasing the pressure again i had a good look around the hot press and i think i may have found a leak. if you look at this picture you can see a drip - would this drip be enough to cause the loss of pressure ? it was very hard to get to but i got two turns on it so hopefully its tighter now

van_beano

sunnyday1234 wrote: »

after increasing the pressure again i had a good look around the hot press and i think i may have found a leak. if you look at this picture you can see a drip - would this drip be enough to cause the loss of pressure ? it was very hard to get to but i got two turns on it so hopefully its tighter now

Again, I'm no expert. But if that pipe is part of the closed heating circuit then that leak would be substantial enough to cause the pressure drop. That pipe may be going to the immersion cylinder from the water tank though? You'll know if the pressure keeps dropping though.

sunnyday1234

van_beano wrote: »

Again, I'm no expert. But if that pipe is part of the closed heating circuit then that leak would be substantial enough to cause the pressure drop. That pipe may be going to the immersion cylinder from the water tank though? You'll know if the pressure keeps dropping though.

not sure . will look closer this evening. either way i had to sort that leak anyway. it did seem to start leaking once i increased the pressure .

Sparkpea

Yes it sounds like a leak somewhere. As already said add leak sealer, I use miracle seal made by ct1.

If that is the leak you've found then tighten the nut if possible

sunnyday1234

Sparkpea wrote: »

Yes it sounds like a leak somewhere. As already said add leak sealer, I use miracle seal made by ct1.

If that is the leak you've found then tighten the nut if possible

so i got up this morning and hte pressure was down a little. Is it normal for it to drop a bit when the heating is off ? Because i turned on the heat this morning then and the pressure was back at normal

Also, where do i add the sealer to ?

Sparkpea

You should be checking your pressure when the system is cold that's the only accurate way to read it. When the system is warm the pressure will rise but it will then drop again once it cools.

You can add leak sooner through a radiator, towel rail, boiler etc. Anywhere on the system really. You might be best getting a plumber to add it though unless your confident you know what you're doing.

sunnyday1234

Sparkpea wrote: »

You should be checking your pressure when the system is cold that's the only accurate way to read it. When the system is warm the pressure will rise but it will then drop again once it cools.

You can add leak sooner through a radiator, towel rail, boiler etc. Anywhere on the system really. You might be best getting a plumber to add it though unless your confident you know what you're doing.

ok thanks. ill monitor it now when cold for a few days and then talk to the plumber

van_beano

You might already know this, but when you bleed a rad and a small bit of water comes out this can cause the pressure to drop as well. So once you repressure, you bleed the rads and then repressure again if needed.

sunnyday1234

van_beano wrote: »

You might already know this, but when you bleed a rad and a small bit of water comes out this can cause the pressure to drop as well. So once you repressure, you bleed the rads and then repressure again if needed.

yep, thtanks

sunnyday1234

ok guys so i have been checking the pressure every morning and evening. it has dropped more and more in the morning (when its cold) but yet when i turn it on it goes to the exact same level every time (which is just under 2). i understand that the pressure will increase when water is hot but if there was a leak and water escaping then the pressure when hot should also be less as there is less water in the system, correct ?

is it just that im not giving it a chance to go totally cold to get the exact reading when cold ? i leave it overnight but if some nights are colder than others, would it drop further ?