Onoff Posted August 26, 2016 Share Posted August 26, 2016 (edited) It never rains but..... For no apparent reason just now the overflow pipe coming out of the eaves started pouring water, not a drop but a constant pouring also it was WARM. Figuring either header tank or CWS tank (25gal) I went up into the loft to have a look. Access is a biatch and then some. All put in by Frodo or someone of similar stature. I have to balance on a partially opened set of steps and squeeze my chest and shoulders up between the pipes to the CWS and header tanks. No room to move and a serious risk of falling off the steps / bringing the whole lot down as its on 3 bits of 4"x2" nailed to the rafters up in the apex of the roof. This is a sketch I did based on a scruffier fag packet one there originally. I've added, a good while back, x2 28mm 2-port valves below the 3-way so I can zone upstairs and downstairs. Works a treat. Pretty sure nothing to do with that. It was the CWS tank overflowing BUT the ball valve on the mains in was shut. On the tank I have: - 1) Mains in at the top via a ball valve - 2) Cold out to the bottom of the hot water cylinder - the thick blue pipe I've just drawn on - 3) Cold out dedicated to the shower pump - 4) Cold out to the bath The cold out to the bottom of the hot water cylinder was warm/hot all the way back up to the CWS tank! In that line down to the cylinder I have a 22mm ball valve. I closed that for a few minutes to stop the hot "back feeding". The overflow ceased. I then opened the ball valve again and everything seems to have settled down. Any suggestions as to what is happening here? Do I turn down the Pump (set on 3 btw)? Or is it to do with the balancing valve do you think? Cheers EDIT: If it's of any bearing and I suspect it may be we were filling up a paddling pool on the patio. Cheating I'd slipped a length of flexible cable duct over the kitchen mixer tap and turned on the hot tap and mains cold fully. Is it that I'd emptied the hot water cylinder or something. Still not sure of the mechanics of it all! Edited August 26, 2016 by Onoff Link to comment Share on other sites More sharing options...
ProDave Posted August 26, 2016 Share Posted August 26, 2016 How was the water being heated at the time? immersion of boiler? If immersion, probably the thermostat failed, water boiling and venting out the expansion pipe. If the boiler, heat exchange coil perforated. If the heating header tank is higher than the CW header tank, the slightly higher head would over fill the CW header tank. Is the hot water running clear or is it dirty? contaminated by the CH water) Time so consider knock down and rebuild? there seems to be a lot of "issues" with your house. Link to comment Share on other sites More sharing options...
Onoff Posted August 26, 2016 Author Share Posted August 26, 2016 (edited) 7 minutes ago, ProDave said: How was the water being heated at the time? immersion of boiler? If immersion, probably the thermostat failed, water boiling and venting out the expansion pipe. If the boiler, heat exchange coil perforated. If the heating header tank is higher than the CW header tank, the slightly higher head would over fill the CW header tank. Is the hot water funning clear or is it dirty? contaminated by the CH water) Time so consider knock down and rebuild? there seems to be a lot of "issues" with your house. Heated by the boiler which is oil. Immersion in the hot water cylinder is not connected / used. Header and CWS tanks sitting on the same level, dodgy wooden platform Hot water is running clear. I did wonder if the coil in the cylinder had split? Or maybe it's the cylinder stat..... Knock, down and rebuild? Wife won't have it. Edited August 26, 2016 by Onoff Link to comment Share on other sites More sharing options...
ProDave Posted August 26, 2016 Share Posted August 26, 2016 Well if water is flowing out, it must be also flowing in somewhere, so which if either header tank is re filling? Another possibility: A thermal mixer on say a shower failed and back feeding mains cold water into the hot water system? Link to comment Share on other sites More sharing options...
Temp Posted August 26, 2016 Share Posted August 26, 2016 (edited) Quote On the tank I have: - 1) Mains in at the top via a ball valve - 2) Cold out to the bottom of the hot water cylinder - the thick blue pipe I've just drawn on - 3) Cold out dedicated to the shower pump - 4) Cold out to the bath If the CWS tank is filling with hot water then one of the pipes that is meant to send cold out will be warm, indicating the source of the problem. Failing that turn off or block them all until the overflowing stops. If the tank isn't very deep you can reach in and put a thumb over each in turn or perhaps even feel where the hot water is coming from. As ProDave said... It's very common for corrosion in hot water tanks to cause a hole allowing water to flow from one side to the other. Ditto the shower mixer problem. Edited August 26, 2016 by Temp Link to comment Share on other sites More sharing options...
Onoff Posted August 26, 2016 Author Share Posted August 26, 2016 Weird. I had had a shower just before we started filling the paddling pool. I wonder could it be that the 25gal CWS doesn't replenish the cylinder quick enough? Time for that UVC maybe! Link to comment Share on other sites More sharing options...
Nickfromwales Posted August 27, 2016 Share Posted August 27, 2016 Does your shower use an impeller pump? Link to comment Share on other sites More sharing options...
riv990 Posted August 29, 2016 Share Posted August 29, 2016 Putting a pipe onto the kitchen mixer tap (high pressure cold low pressure hot ) will have caused a back flow up into the hot water cylinder and up into the cold feed tank and then to overflow Link to comment Share on other sites More sharing options...
Temp Posted August 29, 2016 Share Posted August 29, 2016 On 8/26/2016 at 18:46, Onoff said: EDIT: If it's of any bearing and I suspect it may be we were filling up a paddling pool on the patio. Cheating I'd slipped a length of flexible cable duct over the kitchen mixer tap and turned on the hot tap and mains cold fully. Is it that I'd emptied the hot water cylinder or something. Still not sure of the mechanics of it all! So the overflow stopped on it's own sometime later or is it still overflowing today? Link to comment Share on other sites More sharing options...
Onoff Posted August 29, 2016 Author Share Posted August 29, 2016 The cws overflow was verily pi$$ing out warm 'ish water. I shut the ball valve in the feed from the cws tank to the bottom of the cylinder for maybe a minute. The overflow stopped. There was some gurgling in the cylinder and it all settled down. Been fine since. Link to comment Share on other sites More sharing options...
Nickfromwales Posted August 29, 2016 Share Posted August 29, 2016 Are we deffo talking about the CWS ( cold feed to the hot cylinder ) and not the much smaller F&E ( feed and expansion for the central heating ) ? Link to comment Share on other sites More sharing options...
Onoff Posted August 29, 2016 Author Share Posted August 29, 2016 1 hour ago, Nickfromwales said: Are we deffo talking about the CWS ( cold feed to the hot cylinder ) and not the much smaller F&E ( feed and expansion for the central heating ) ? 100% the CWS tank, NOT the little one that tops up the CH etc. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted August 29, 2016 Share Posted August 29, 2016 How hot is is it getting? Long shot but - Its not the sun (general hot weather) heating the inlet water to the tank some how? Link to comment Share on other sites More sharing options...
Onoff Posted August 29, 2016 Author Share Posted August 29, 2016 1 hour ago, MikeSharp01 said: How hot is is it getting? Long shot but - Its not the sun (general hot weather) heating the inlet water to the tank some how? Definitely not the sun. The 22mm pipe that comes down from the CWS tank into the cylinder was quite hot and feeding back into the bottom of the CWS tank. It was mixing with the mass of cold and overflowing thus what was coming out of the overflow was warm. The CWS tank ball valve was closed. Link to comment Share on other sites More sharing options...
Nickfromwales Posted August 30, 2016 Share Posted August 30, 2016 Drain down the central heating with the cold mains feed to both tanks turned off ( float valves ). If the CWS empties over a couple of hours also then it's a perforated coil. You need to be draining at a point that ensures the cylinder coil is getting drained, ideally, as that will give a faster indication. 1 Link to comment Share on other sites More sharing options...
Onoff Posted August 30, 2016 Author Share Posted August 30, 2016 1 hour ago, Nickfromwales said: Drain down the central heating with the cold mains feed to both tanks turned off ( float valves ). If the CWS empties over a couple of hours also then it's a perforated coil. You need to be draining at a point that ensures the cylinder coil is getting drained, ideally, as that will give a faster indication. Thanks (as usual). One oddity that may have some bearing and point towards a breach in the coil is that every now and then the CH makes a gurgling noise almost as if it's suddenly lost water / has air in and is filling up. You can actually hear water running in the pipes. Then it rights itself. Whether this coincides with the CWS overflowing I couldn't really say. Maybe the time has come to carefully think about a new cylinder, whether to go to a UVC etc. Assume they're OK coupled with an oil boiler? I assume I can keep the CH "unvented" and just have just the hot water at mains pressure? Link to comment Share on other sites More sharing options...
Nickfromwales Posted August 30, 2016 Share Posted August 30, 2016 Yes, open pipe for primary is fine. Certainly a good time to upgrade IF the cylinder is U/S. Link to comment Share on other sites More sharing options...
ProDave Posted August 30, 2016 Share Posted August 30, 2016 But finish one job before you start yet another. Link to comment Share on other sites More sharing options...
Onoff Posted August 30, 2016 Author Share Posted August 30, 2016 36 minutes ago, ProDave said: But finish one job before you start yet another. This might be one I have to fit in! Tried isolating the feeds to the ballcocks on the header & cws tanks, wouldn't budge! Brass stopcocks on both. Link to comment Share on other sites More sharing options...
Onoff Posted August 30, 2016 Author Share Posted August 30, 2016 Can only get a picture from below. Access is be squeezing up between the 15mm mains to the header and the 22mm out to the bath. As this is less than my shoulder's width it's one arm up first etc. Tight back to front on the chest too. All whilst standing on steps. Believe it or not I DO know where all the pipes go! One day this will hopefully be a distant memory: Link to comment Share on other sites More sharing options...
Onoff Posted October 28, 2016 Author Share Posted October 28, 2016 Could a faulty 3 port valve have caused the problem in the OP I wonder..... Looking at the diagram above, if hot was letting by the 3 port it would have maybe been heating the water in the cylinder constantly rather than just when the cylinder stat called for it? Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 28, 2016 Share Posted October 28, 2016 If your boiler stat was set too high then maybe. The cylinder would only have heated to the set temp of the boiler, so anything above 70oC may have started a bit of excessive expansion plus it would have been sustained so perhaps see if it all settles down now ? Link to comment Share on other sites More sharing options...
Temp Posted October 28, 2016 Share Posted October 28, 2016 Hopefully sorted by now :-) Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now