Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
Discuss Gurgling boiler + Air in CH + FE tank in the Boilers area at Plumbers Forums
Thanks to you and John for engaging with me and for all your help. I have attached some images of my system in the loft. What I noticed when taking pics was that bubbles popped up from the F+E cold feed. Am not too sure if this should be the case or not and whether this explains why the F+E tank has got dirty again given I gave it a thorough clean 2wks ago. In any case from the pics, it looks like a traditional system though can't rule of they combine lower down. I can't make heads or tails from the piping in airing cupboard. The exposed copper pipes I think feed into the 2 showers we have upstairs. I would imagine that another 2 should be air vents for the F+E and the CWS tank.
Would be great to see what you think. Cheers.
View attachment 37315
View attachment 37316
View attachment 37317
View attachment 37318
View attachment 37319
Concentrating on the Boiler & F&E system, you show the pump pumping through the M.filter and then into the boiler, you are also showing another (green) pipe Teeing into that just before the boiler, is this the cold make up do you think?, it would normally (but not necessarily so) be of smaller diameter (1/2") than the pipe (3/4") its joining. Vent Pipe: It should be relatively easy to follow it from the attic down through the attic floor and see it it is in fact Teed off the hot water cylinder coil top entry.
Also can you confirm that the lever valve is on the same bit of piping as the MV and that the MV is feeding the coil top entry.
Have you opened the lever valve fully?
Is the pump now on speed 1? and if so what effect if any has it had on boiler cycling etc.
Note: IF the cold feed is Teed in at the boiler entry then its possible that the boiler H.exchanger has become partly fouled and the pump is now forcing water up through the cold feed and into the F&E tank (hence bubbles) but someone will have to ensure that it is in fact plumbed in this manner.
Thanks Jon,Another question (will they ever end), when you were circulating the chemical cleaner for two weeks, I assume the heating system was i/s, any problems during this period or did they begin after drain down and refill with inhibitor?.
Sure no worries John.Thanks for all you help and suggestions. Really appreciate it.Afraid I am clean out of ideas, lets see what your plumber says tomorrow?.
Final say before "D" day tomorrow, IMO that lever valve is a balancing valve on the hot water coil, to give a reasonable cylinder warm up time but divert as much water as possible to the CH when both systems are calling for heat. They are often fitted in the form of a gate valve on the return of the coil and were always fitted in systems with no zoning.
Thanks!1A. Boiler heat exchanger blocked.
Thanks John for asking but no unfortunately not. Plumber #2 was a nice chap with clear experience and knowledge but said that the fault could be at one or many places! So none the wiser unfortunately.Hope you are sorted, there is a very interesting thread here of a few months ago "Air problem in open vented system after boiler change"
How could one one run a pump without the boiler on?Re possible blockage of cold (green) feed at boiler, if you feel this as high up as you can it may be warm as you did see bubbling in the F&E tank.
No simple answer then. Could you run the circ pump for a extended period (would need separate supply) with boiler off and see if noise persists.
I think the wiring of the pump is beyond my remit.The wiring would have be removed in the pump terminal box and a live supply wired in there, before doing this the MVs should be manually opened with the lever(s) on the side(s).
The water level falling in the F&E tank (whatever the reason) would indicate that the cold feed isn't blocked as that is the only connection to the system apart from the vent. Can you tie up the ball cock as suggested by the plumber and see if the level changes over say 24 hrs, checked when system is cold, maybe first thing in the morning.
Thanks for the suggestion John of Teeing off the vent and cold feed. I will check this out. I did read the thread you had kindly suggested but am unsure if they ever solved their issue (which involved a much larger level of change to the system than I have). The boiler set point temperature is a gauge and not numbered. Initially it has been on quite high and I have turned it done significantly. Can't say I see any improvement to the system tbh. The short cycling still exists, air sound still trickling somewhere in the pipes and poor performance in some of the rads. I will try to set to minimum tonight. Its getting to a point where I can't see this being ever resolved but I shall persevere before considering a sealed system. I' m not inclined yet to go down this road until I am absolutely convinced that my piping will be able to withstand it. Thanks!Should have asked before, what is the boiler set point temperature? and have you tried running at say its minimum to see does it have any affect on the noise?.
Thanks John, I appreciate your advice and details for the conversion. I really just find it a little bit disheartening that it would need to go down this road when clearly the system has been in good operations for the last 4oyrs and that one set of minor work has created this imbalance!That thread was very interesting in that the system is fine at 65C but not at 70C, that was converted to a combined feed & expansion and it still did not solve the problem so maybe be a waste of time in your case, a leaking boiler HX was/is? the main suspect there I think.
If it (yours) was my system, I would, in view of old pipework etc, convert it to a semi sealed system, it would only entail installing a AAV on the removed vent, fitting a swing check NRV in the feed and installing a 12 litre E.vessel teed in just before the circ pump. You already will have a static system head of ~ 0.5 bar, on conversion to the above system, a 12 litre E.vessel with a pre pressure of 0.5 bar, will only rise to ~ 0.75 bar with hot system and that certainly won't pose any pipework problems.
Sealing the system and installing the E.vessel before the circ pump will almost guarantee no ingress of air, then just get rid of the entrained air.
Would also suggest removing the pump head and checking for any blockages in pump ports and the impeller, this can be done at anytime by just shutting the pump isolation valves and removing the pump head.
I was looking at the Main HE boiler manual today and it states that it has a pump overrun of 2 mins which implies that there is, or should have been, a ABV (automatic bypass valve) installed somewhere on the system, have you got one of these?, it will be fitted between the flow & return probably fairly close to the boiler, if this is fitted and is not set up properly or malfunctioning then it will cause all sort of problems as you could be short circuiting the CW/HW systems, have a good look around for this.