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Post by fastflowfred on Nov 4, 2018 10:06:11 GMT
Hi, first post - be kind please to a DIY disaster area. Tom asked me to pop over here after watching one of his vids on why rads don't always drain downstairs. I get why now but he didn't say what to do about it sadly.
In context: I have a new 3 port valve to fit, so have drained down the heating to do that. So, turned off the water & I attached the hose to the bleed off valve on the rad at the back door and drained down, opening the bleed valves upstairs rads as I went and allowing the to suck in air. So far so good.*
(* I actually managed to ruin the bleed off valve on that rad - a stupid Myson in-line design - by not knowing and leaving the grub screw in and attaching the hose. Of course, when the water had all 'gone', so had the grub screw down the hose and out into the grid ! So twenty unsuccessful minutes of furtling around in the grid to try & find it later, i have decided to just buy and replace it with a better valve design, in the meantime i botched the missing grubscrew with ano i had and ptfe tape as a temp solution 'til i put the new one on. Live & learn, eh?)
I put a cleaner in the system, refilled and ran the heating but the three rads in question didn't heat up - they did previously i.e. before the first drain down and all the others work brilliantly, which is confusing as i'm thinking a possibility is a pipe blockage somewhere? See below.
So drained down again (still 'empty' & the wife is cold as we speak) except the three rads. When i open the bleed valves, they actually shoot water out not suck air in? They do this even when the inlet and lockshield at the other end are shut? On the one by the front door )with ano drain off valve) i carefully un-did the bleed grubscrew and opened the bleed valve - still nothing came out?
Anyway, the rads upstairs seem to have drained but three of the four downstairs haven't. The kitchen one with the bleed off valve has but the others are, i assume, on a different pipe run (& I can't see the runs as such as it's all underfloor / designed in and am not 'plumber enough' to work out which go where).
Obviously, i could take the rads off but it seems like there is a blockage of some sort in the pipe run or it is being 'held' there in some way? Would taking them off disrupt something enough to unblock?
So any ideas / help much appreciated. In the meantime i could actually get on and swap the 3 port i guess or should i wait til this is sorted in case any sludgy stuff will mess that up?
Thanks.
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Post by rocketmanbkk on Nov 4, 2018 10:28:50 GMT
Is the 3 port valve on the first floor?
If so, you might be able to swap it by just draining first floor
The dads you say are empty, have you tried opening the valve on each side to see if water is getting through?
Do you have a F&e tank in the loft? Does it have water in?
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Post by rocketmanbkk on Nov 4, 2018 10:29:50 GMT
You can also shut all other valves to rads & trying forcing the water through each road in turn then balance system
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Post by fastflowfred on Nov 4, 2018 10:43:34 GMT
Is the 3 port valve on the first floor? Yes.If so, you might be able to swap it by just draining first floor. Done it now anyway, it's empty bar those three.The dads you say are empty, have you tried opening the valve on each side to see if water is getting through? Yes, opened the inlet / outlet valves in all the combinations of on / off and while there was water in and the pump running (when they weren't getting hot) and also, when drained and (in theory) no water in - except there was ! I think i understand from Tom's vid diagram why there might be water held in but not why the expell water not suck in air and why on the drain valve on one of those rads, it didn't come out at the bottom despite opening the bleed to let air in? Do you have a F&e tank in the loft? Does it have water in? Yes, I do sorry, that is drained & tied off while i sort this. It is empty bar the bit sloshing around at the bottom. |
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Post by fastflowfred on Nov 4, 2018 10:46:22 GMT
You can also shut all other valves to rads & trying forcing the water through each road in turn then balance system I guess. I think i can safely assume that all my upstairs water has dropped so i could do the 3 port first? Then refill (after replacing that silly drain off inket valve that i lost the grib screw for). Then try all the forcing by truning off each rad in turn / balancing ? |
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Post by rocketmanbkk on Nov 4, 2018 10:48:42 GMT
Is the 3 port valve on the first floor? Yes.If so, you might be able to swap it by just draining first floor. Done it now anyway, it's empty bar those three.The dads you say are empty, have you tried opening the valve on each side to see if water is getting through? Yes, opened the inlet / outlet valves in all the combinations of on / off and while there was water in and the pump running (when they weren't getting hot) and also, when drained and (in theory) no water in - except there was ! I think i understand from Tom's vid diagram why there might be water held in but not why the expell water not suck in air and why on the drain valve on one of those rads, it didn't come out at the bottom despite opening the bleed to let air in? Do you have a F&e tank in the loft? Does it have water in? Yes, I do sorry, that is drained & tied off while i sort this. It is empty bar the bit sloshing around at the bottom.If there f&e tank is empty there won’t be enough water in the system & the pump might run dry. Sometimes got ground floor rads you need to drain rad by rad Let the f&e tank fill, bleed whole system, turn heating on with all rad valves open. Then report back |
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Post by rocketmanbkk on Nov 4, 2018 10:49:37 GMT
If you’ve got TRV valves make sure the pin isn’t stuck.
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Post by tomplum on Nov 4, 2018 10:54:44 GMT
hello fastflowfred welcome to the brewcabin, I believe what you have here is the dreaded air lock, Its a plumbers nightmare but we will be able to shift it, first of all do any work that needs doing like change that 3 port and renew the broken drain off you don't want to move the airlock then start draining again, then fill up as normal, Fill the downstairs rads first then the upstairs ones, air rises so hopefull most of the air will collect in the upstairs rads, as you are filling you should hear the tank upstairs filling up, if you cannot, check its getting water and the water is entering the system, If its not, try drian ing off at drain off, that might pull it through, when you get that tank filling and running, continue filling the rads, when you get this far, come back and report,  |
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Post by lauraleeks on Nov 4, 2018 11:08:25 GMT
Just a point about the downstairs rads not draining. They are almost definately on a drop feed from 1st floor and as such will not drain back up over and down through your drain cock. Some systems are temperemental and do cause problems re filling, through air locks or blocked feed pipes. A common way to get round this is by bottom filling with a hose pipe via your drain cock, or anywhere you can tap into system. this usually forces the air up and out. Hope this helps.
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Post by fastflowfred on Nov 4, 2018 11:17:34 GMT
hello fastflowfred welcome to the brewcabin, I believe what you have here is the dreaded air lock, Its a plumbers nightmare but we will be able to shift it, first of all do any work that needs doing like change that 3 port and renew the broken drain off you don't want to move the airlock then start draining again, then fill up as normal, Fill the downstairs rads first then the upstairs ones, air rises so hopefull most of the air will collect in the upstairs rads, as you are filling you should hear the tank upstairs filling up, if you cannot, check its getting water and the water is entering the system, If its not, try drian ing off at drain off, that might pull it through, when you get that tank filling and running, continue filling the rads, when you get this far, come back and report,  Thanks oaplum. Yes, that sounds like a plan. I need to go & get a new drain of valve first and then crack on. Not 100% sure i know what you mean to "fill the downstairs rads first..." - I assume you mean filling 'normally' by turning on the water to the f&e tank & letting it flow down? In the words of Arnie, i have no doubt that "I'll be back"for more advice. But just checking: my upstairs sounds like it is dry to swap the 3 port ? Thanks. 😉 |
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Post by fastflowfred on Nov 4, 2018 11:24:57 GMT
Just a point about the downstairs rads not draining. They are almost definately on a drop feed from 1st floor and as such will not drain back up over and down through your drain cock. Some systems are temperemental and do cause problems re filling, through air locks or blocked feed pipes. A common way to get round this is by bottom filling with a hose pipe via your drain cock, or anywhere you can tap into system. this usually forces the air up and out. Hope this helps.
Thanks. As per oaplumb's post i better do the 'work' of swapping the 3 port and the drain valve first. But then, to understand you correctly: fill up from the (new) drain off valve at the bottom to force the water (& air) up, yes? Just the drain off in reverse i think you mean. I guess you just need to do that until it reaches the f&e ? Sure that has an overflow pipe anyway just in case. Do I need to have any rad bleed valves open during the process? |
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Post by fastflowfred on Nov 4, 2018 11:29:03 GMT
Just a point about the downstairs rads not draining. They are almost definately on a drop feed from 1st floor and as such will not drain back up over and down through your drain cock. Some systems are temperemental and do cause problems re filling, through air locks or blocked feed pipes. A common way to get round this is by bottom filling with a hose pipe via your drain cock, or anywhere you can tap into system. this usually forces the air up and out. Hope this helps.
Ano option: all my downstairs have a drain cock on (did they anticipate this exact problem) so if it comes to it, i could drain them, each one, individually i guess? (Not a preferred option as they as they are far less accessible.) However, as i mentioned in the OP, i did try a drain on the one near the front door but it wan't for draining and actually had pressure in enough to spurt water out rather than suck air in? |
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Post by fastflowfred on Nov 4, 2018 11:29:57 GMT
If you’ve got TRV valves make sure the pin isn’t stuck. Thanks. No TRVs. Rightly or wrongly. |
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Post by tomplum on Nov 4, 2018 11:47:43 GMT
hello Fred, No don't try filling from the drain off, we might come to that if it gets desperate, ( I'm tom by the way) , what I mean is, if the tank upstairs is not going into the system, put a hose pipe on a drain off thats convieniant and works and drain the water from there and leave it running, then check the tank is filling and running in the system, This will suck the water from the tank, when its flowing good, shut the drain off and let the system fill up.
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Post by fastflowfred on Nov 4, 2018 11:54:18 GMT
hello Fred, No don't try filling from the drain off, we might come to that if it gets desperate, ( I'm tom by the way) , what I mean is, if the tank upstairs is not going into the system, put a hose pipe on a drain off thats convieniant and works and drain the water from there and leave it running, then check the tank is filling and running in the system, This will suck the water from the tank, when its flowing good, shut the drain off and let the system fill up. Thanks Tom. Gotcha. In the meantime - just checking while i do all the work, the hot water cylinder fills independently from the CW tank and so i can just use the immersion heater to heat hot water for showers etc if needed? In other words, as it stands, i have the f&e tank ballcock tied off to not fill but that has nothing to do with the hot water cylinder. Is that correct please? The wife is already upset at no heating so no showers could be problematic : ) Edit:And, are the rads (the system as such) OK with no water in ? Or will that promote rusting etc? Obviously i want to do the jobs asap but might not be able to get a valve today. |
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