Gurgling/water flowing noises from boiler-no CH switched on

[VeeDubMan]

Back in March, we moved into a house which has a ground floor extension with radiators being fed from pipework from above. Thanks to this site, I found out that this was the reason why the small radiator in the bathroom always needed bleeding. I\\\'ve now fitted an automatic bleed valve to sort that issue out, but in doing this I found out there was loads of sludge in the central heating system and the expansion tank AND the ball-cock valve had completely seized on the expansion tank too!

Anyway, all sorted now (sludge removed, flushed etc.), but ever since, the hot water system seems to be making loads of gurgling noises when heating up the water. The central heating is now off for the summer, so I\\\'m not sure if the gurgling was happening before and the noises were just masked by the air gurgling in the central heating system or if these are new noises just associated with the hot water system. It almost seems like the hot water system needs bleeding. Can this be done?

 

[chrishutt]

Not much we can say without some info on your system. What boiler, controls, motorised valves (3 port, 2 port), fully pumped or gravity to HW cylinder, etc. Also have you looked at what's happening at the feed and expansion tank when it gurgles?

 

[Nige F]

Back in March, we moved into a house which has a ground floor extension with radiators being fed from pipework from above. Thanks to this site, I found out that this was the reason why the small radiator in the bathroom always needed bleeding. /quote] Sorry, but a drop feed to rads on a system is not why air was/is gurgling+ needing bleeding .The air is getting in somewhere , which is unfortunately far too common

 

[VeeDubMan]

Well, as a complete newbie to plumbing, I guessed that as the systems are meant to contain water and not air, they should be sealed and no air should get in. However, I was informed by a couple of plumbers (and this site somewhere) that it was due to the drop fed rads. No, I couldn't figure that out either, but at least the trapped air ca now escape.

 

[VeeDubMan]

Fortunately, the previous owners had kept all the documents relating to the system and even a wiring diagram of what's what:

Boiler is a Baxi Solo wall mounted RS and I have the documents for a 3 port motorised valve (HSV3), a spring return diverter valve, a PTT2 electronic cylinder thermostat a PRT2 room thermostat and a Grundfos domestic circulator.

The boiler is on the wall in the dining room (which was the kitchen at one point) and according to the wiring diagram, there is the pump and the motorised valve above it in a trap door under the floor in the corner of the bedroom above (I've yet to look in there as there's a huge wardrobe on top of it).

Looking at the Baxi instructions it looks like this is a fully pumped system as the pump is above the boiler (??).

One other question, where does the cold water that gets heated up by the boiler come from? I'm hoping not from a tank in the loft as they're both grim. The cold water tank is passable but has some bits in it and the small plastic expansion tank is just for the central heating yeah?

I'm learning all the time here, so be patient

 

[ollski]

One other question, where does the cold water that gets heated up by the boiler come from? I'm hoping not from a tank in the loft as they're both grim. The cold water tank is passable but has some bits in it and the small plastic expansion tank is just for the central heating yeah?

I'm learning all the time here, so be patient

The small tank is the water the boiler sends round your radiators and also uses to heat an element in side the cylinder for hot water. The hot water that you bath and generally ablute in comes from the bigger tank in the loft.

 

[Nige F]

Any chance of some pics?........cylinder layout.......Pump+valve are usually in cupd. next to cyl. and cold feed+vent are there too on suction side of pump...then 3 porter...and off to rads + thru coil in cyl.....Don`t bother moving wardrobe yet, but pics or diagram would be good

 

[VeeDubMan]

I'll see what I can do on the pics front.

So, when I drained the rads when I moved a radiator, would that have drained the hot water circuit too? I have 3 drain points on the rads in the lounge, dining room and the hall. Having listened to the noises in different locations at 06:30 this morning when the HW came on, it definitely sounds like air is in the system between the boiler and the HW tank and the gurgling is through the boiler. There is nothing abnormal happening at the expansion tank end.

Is there a bleed valve on the pump or boiler like there is on a rad?

 

[ollski]

There will be a vertical length of pipe somewhere with some sort of screw cap on the top, this is your pipework bleed point.

 

[Nige F]

I'll see what I can do on the pics front.

So, when I drained the rads when I moved a radiator, would that have drained the hot water circuit too? YES. There is nothing abnormal happening at the expansion tank end.........OK

 

[Softus]

So, when I drained the rads when I moved a radiator, would that have drained the hot water circuit too?

Yes.

I don't wish to appear rude, but why did you drain the system when you don't understand how it works?! If you didn't refill the system AND VENT IT, but then allowed the boiler and pump to operate then you stand a good chance of ruining them both.

There is nothing abnormal happening at the expansion tank end.

What does this mean? Did you observe that the F&E cistern emptied when you drained the system? Did you clean out any/all sludge? Did you observe water leaving the system while refilling? Did you add any chemical inhibitor? Did you test that the system was full?

 

[VeeDubMan]

Well the insructions I had didn't mention anything about the HW circuit so I assumed just draining the CH circuit left the other one alone.

Lesson learnt there then.

Here's what I did anyway:

-valve on ballcock in expansion tank was seized so tank wouldn't refill anyway, but loads of sludge in there which I manually (scoop and bucket) removed before letting the remaining water flow through the system.
-all rad bleed valves were removed (in the right order) to allow water to leave the system and the rads were all drained via drain off points
-replaced radiator in kitchen
-fitted new ball cock
-added sludge cleaner to the expansion tank
-replaced rad bleed valves
-turned supply back on
-expansion tank refills and fills rads
-made sure water had reached the drain valves again
-bleed all rads in correct order
-let sludge remover circulate for whatever period it said on container
-rads were all hot top and bottom after this (on the hottest day of the year too!)
-repeat most of above steps and add inhibitor


I'm sure there's just air in the HW circuit now which I've got to remove, once I've found the right bleed for that.

Thanks for everyone's help so far.

Cheers

 

[Softus]

Well the insructions I had didn't mention anything about the HW circuit so I assumed just draining the CH circuit left the other one alone.

I'm very curious to know what instructions there were, so that the author can be suitable chastised.

Lesson learnt there then.

And hopefully not an expensive one for you!

The rest of what you did sounds correct. A correctly installed system has vents at all the right places. Often there is one at the flow into the DHW cylinder.

 

[Nige F]

Softus is right about correctly installed systems. And I`ve installed a few over the years.......but I`ve seen more incorrect,sludged,aerated ones than the Correct ones I`ve done And I am puzzled because there are but a few principles to follow for a domestic sized heating system that is fully pumped, with motorized valve/s controlling Domestic water/heating water Maybe it was something to do with me doing one a week on average, for an employer.......when there were guys doing 2 a week for the same employer, on a self- employed basis