Hi there,
A year ago we bought a repossession as our first home, with ten weeks to turn it around. We were in a rush to get in the house (we were running out of time as our tenancy was due up) when we discovered the boiler needed replacing. With limited cash, a friend offered to install the heating system as I, at the time, knew virtually nothing about plumbing - about 80% of the pipework was replaced, along with 4 of 7 rads and a new EcoTec Vaillant 838 Exclusive boiler installed. Yes, the boiler is hugely overspecced for the house, but we wanted a good flow rate for the shower and it's range rated down on the heating side. The gas side of things was seen to and signed off by a GasSafe engineer, and we were happy. For a bit...
After about 2 months we started having an issue with the boiler - Vaillant came out (the guy was great) and he was surprised to see the boiler quite mucky. Looking back though I wish I'd ripped out all of the rads and replaced all pipework not buried in concrete, but we didn't. The Vaillant chap replaced the pressure valve and suggest I get a Fernox TF1 or similar. This I did, and I started teaching myself about the heating system. Since then, I've slowly been replacing all the old rads as money permits, each time draining down / washing through the TF1, emptied the system, washed through from the filling loop on the boiler (out of a tail on one of the rads), then treated the system with Sentinel x400 (having left it in for weeks at the time) ready for the eventual final flush when all rads were done and final treatment with inhibitor.
The one thing I absolutely kick myself for is that I didn't add X100 last time I flushed out the x400 - I'd planned on removing the rads only a week or so after the last x400 flush and rinsing them through with a hose before refitting but work went crazy and I never got around to it, meaning the system probably ran for 5 months with neither system cleaner nor inhibitor in it until I rinsed them last weekend and added X400.
The current problem
Around May when we turned the heating off and, when showering, noticed the towel radiator was getting mildly warm. It got increasingly worse until I finally called Vaillant - they initially diagnosed a faulty diverter valve, then faulty PCB. Both changed, no difference, the fault remains. The last chap commented that the water in the boiler was still a little sludgy and we should get the system cleaned before I get Vaillant back out, so I decided to finally sort it.
I drained down the system last weekend and took each radiator off the wall, removing them outside and washing them through with a hose. I got very little sludge out of them, but not much - the only slightly nasty one was the only original radiator left in the house and I don't want to change that as it's imperial not metric, a new rad will either be too small, or not fit under the window, but even then the sludge wasn't too bad. I've now treated the system with X400 and the water is running clear (albeit it was running clear previously when I washed through the system and I still got some black sludge out of some of the rads when I washed them through). I'm now going to try the mains flush as suggested on this forum (here), then I'm going to try X800, run the system hot for an hour two and mains flush a second time (Sentinel tell me x800 is not just for power flushing and should give good results with a mains flush). Post x800 treatment and second flush, I'll finish off with x100 inhibitor.
I'd love to pay for a PowerFlush but just can't afford it at the moment and, from the advice on here, a decent flush with mains (and having taken most of the radiators off and washed them through anyway) should go some way to achieving similar results.
Once all is now flushed, I'll then get Vaillant back out to the boiler. I still don't understand why the heating circuit is opening on drawing hot water when they've replaced both the diverter valve and PCB - anyone have any ideas? At least hopefully they'll then come back out to a clean system
I suppose the morale (morales?!) is (are!):
1) not replacing all the rads, or taking the time to take them off and flush them through with a hose when fitting a system, was a false economy,
2) new boilers seem very fickle with regard to even slight sludge, even when paying for a top boiler from a top manufacturer,
3) don't run a system without inhibitor - even for a short period, and
4) Fernox TF1 is awesome but no substitution for a proper flush and inhibitor
5) this forum is a godsend for advice!
I'd just welcome any comments on the above, and wanted to share the somewhat painful lessons I've learned. I'd be particularly interested to hear any comments on the diverter valve issue - I just don't see why a brand new diverter valve was not closing properly on hot water demand.
A year ago we bought a repossession as our first home, with ten weeks to turn it around. We were in a rush to get in the house (we were running out of time as our tenancy was due up) when we discovered the boiler needed replacing. With limited cash, a friend offered to install the heating system as I, at the time, knew virtually nothing about plumbing - about 80% of the pipework was replaced, along with 4 of 7 rads and a new EcoTec Vaillant 838 Exclusive boiler installed. Yes, the boiler is hugely overspecced for the house, but we wanted a good flow rate for the shower and it's range rated down on the heating side. The gas side of things was seen to and signed off by a GasSafe engineer, and we were happy. For a bit...
After about 2 months we started having an issue with the boiler - Vaillant came out (the guy was great) and he was surprised to see the boiler quite mucky. Looking back though I wish I'd ripped out all of the rads and replaced all pipework not buried in concrete, but we didn't. The Vaillant chap replaced the pressure valve and suggest I get a Fernox TF1 or similar. This I did, and I started teaching myself about the heating system. Since then, I've slowly been replacing all the old rads as money permits, each time draining down / washing through the TF1, emptied the system, washed through from the filling loop on the boiler (out of a tail on one of the rads), then treated the system with Sentinel x400 (having left it in for weeks at the time) ready for the eventual final flush when all rads were done and final treatment with inhibitor.
The one thing I absolutely kick myself for is that I didn't add X100 last time I flushed out the x400 - I'd planned on removing the rads only a week or so after the last x400 flush and rinsing them through with a hose before refitting but work went crazy and I never got around to it, meaning the system probably ran for 5 months with neither system cleaner nor inhibitor in it until I rinsed them last weekend and added X400.
The current problem
Around May when we turned the heating off and, when showering, noticed the towel radiator was getting mildly warm. It got increasingly worse until I finally called Vaillant - they initially diagnosed a faulty diverter valve, then faulty PCB. Both changed, no difference, the fault remains. The last chap commented that the water in the boiler was still a little sludgy and we should get the system cleaned before I get Vaillant back out, so I decided to finally sort it.
I drained down the system last weekend and took each radiator off the wall, removing them outside and washing them through with a hose. I got very little sludge out of them, but not much - the only slightly nasty one was the only original radiator left in the house and I don't want to change that as it's imperial not metric, a new rad will either be too small, or not fit under the window, but even then the sludge wasn't too bad. I've now treated the system with X400 and the water is running clear (albeit it was running clear previously when I washed through the system and I still got some black sludge out of some of the rads when I washed them through). I'm now going to try the mains flush as suggested on this forum (here), then I'm going to try X800, run the system hot for an hour two and mains flush a second time (Sentinel tell me x800 is not just for power flushing and should give good results with a mains flush). Post x800 treatment and second flush, I'll finish off with x100 inhibitor.
I'd love to pay for a PowerFlush but just can't afford it at the moment and, from the advice on here, a decent flush with mains (and having taken most of the radiators off and washed them through anyway) should go some way to achieving similar results.
Once all is now flushed, I'll then get Vaillant back out to the boiler. I still don't understand why the heating circuit is opening on drawing hot water when they've replaced both the diverter valve and PCB - anyone have any ideas? At least hopefully they'll then come back out to a clean system
I suppose the morale (morales?!) is (are!):
1) not replacing all the rads, or taking the time to take them off and flush them through with a hose when fitting a system, was a false economy,
2) new boilers seem very fickle with regard to even slight sludge, even when paying for a top boiler from a top manufacturer,
3) don't run a system without inhibitor - even for a short period, and
4) Fernox TF1 is awesome but no substitution for a proper flush and inhibitor
5) this forum is a godsend for advice!
I'd just welcome any comments on the above, and wanted to share the somewhat painful lessons I've learned. I'd be particularly interested to hear any comments on the diverter valve issue - I just don't see why a brand new diverter valve was not closing properly on hot water demand.