We are having a nightmare with our old hot water/heating system. It appears that air is getting into the system when heating is switched on. Cutting a long story short, it looks like the feeder tank is blocked so cannot fill system. I am going to try and unblock using (part no: 11325) drain unblocker - nothing to lose as system being totally replaced in 9 weeks. However, if anyone has any thoughts please let me know and what position should valve by bolier pump be set to (this is the valve that contols automatic heating/hot water) - should it be auto, manual or in between the two? Thanks for any advice!
Looks like the cold feed/expansion pipe is blocked somewhere near the first restriction in the pipe(usually bend or elbow) especially if it is a 15mm pipe. I suggest renewing pipe between tank and entry point into circuit. The diverter valve should be set to auto position and you should feel a spring resistance on the lever when closed. The lever will be in mid-position when the boiler is supplying both hot water and heating
Nobby Thanks very much for the reply and info. I am going to have a go at unblocking and if that fails then will try to replace the pipe as you say. Nothing to lose as system being replaced in 9 weeks but mighty cold and expensive to keep heating water from emersion !
Nobby Just a thought, what does the 'Manual'position do? I read that it is for filling and emptying the system? Is that right and how do you use it? (I am, obviously, not a plumber!)
cityneil just to let you know what the manual lever on the diverter valve does, if you push it all the way across under spring pressure(when power turned off) and push lever up slightly to lock in open position. This allows you to drain down or fill up the system as it opens the valve water port. When you introduce power back to the valve again, the lever will spring return to normal position. Hope this helps?
Nobby I think so, so if I want to fill the system I have to lock in open position. Will system fill automatically? We constantly get air into the system. Must be a leak somewhere.
connect a hose pipe about 2 foot long from the cold tap in the kitchen to the hot tap in the kitchen turn on the cold tape gently and look for air bubbles in the cistern(feeder tank) this should cure the problem
Quite common in indirect systems that used Fernox whereby it was not properly diluted into the system. Put a hose from the mains on the expansion pipe that loops over the 10 gallon expansion tank. Turn on and it will force the blockage back into the expansion tank. Its a 2 person job and make sure the overflow is clear for the excess water to run out off. >))
Hey Thanks for yet more advice, I am game to try anything. Cold again due to no heating and am rapidly losing sense of humour, although got enough to get another plumber and wallet out - yet!
I had the exact same problem a year ago and it was the 15mm elbow as it goes into the boiler from the feeder tank that was blocked .... a few taps with a mallet cleared it! In saying that I was advised by Scottish Gas (under their 3* plan at the time)that I should disconnect and cap the pipe before it goes into the boiler and reconnect the feed from the feeder tank into the feed to the pump as this was the now recommended way and they estimated that it was an hours work and they would do the job for £199 + VAT + parts .....HA HA, must have thought I was zipped up the back! 1/2hrs work 1-metre of pipe, 15mm T-piece,a 15mm blank and job done .... love to know how they justify their prices!
Sparkyman Ta, love the idea of hitting my plunbing with a hammer, great satisfaction to be had! Will give it a go.