Gunk still in rad pipes around pump after cleaning with Sentinel X400

[Circuital]

Evening all,

I've recently cleaned my F&E, microbore central heating system using Sentinel X400 and this led to the cold rads heating up again, so a success in that respect. Now, after a week of the X400 circulating, today I cleaned the F&E tank again (much cleaner water), drained down the system, refilled it and drained it again to flush it all out. The water that came out was pretty clear.

However, when I removed the existing pump to replace it, a lot of gunk is still coming out of the pipes (see pic attached). So now i'm unsure about whether or not to replace the pump as I don't want to clog up the new one. I'm hoping someone could kindly offer some wisdom on the following points:

1. I only used 1L of X400 for a system of 12 rads. Was this too little?

2. Should I refit the old pump and run some more/different cleaner through the system before draining down and flushing it again, before fitting the new pump?

or

3. Should I try to clean out the pipes near the rads as best as possible using some thick wire (e.g. twin and Earth) and fit the pump anyway?

Any suggestions are greatly appreciated!

 

[Mottie]

I don’t know how you did it but when I used x400 to give my system a flush, I had the pump on max speed and went round closing off rad valves so that the max flow was going through just one rad at a time but that was only after I had removed and physically flushed each rad individually until they ran clear. You might need another dose.

 

[Circuital]

Ahh, your way sounds like a much better method. I just followed the instructions on the Sentinel website, keeping the X400 in for a week, running it for 3 hours initially and then putting on the heating for a couple of hours each week:

"Sentinel X400 should be circulated, preferably at normal operating temperature, with all valves open and the pump turned to maximum flow for a minimum period of 3 hours. Where systems are badly fouled, a longer period of circulation (e.g., up to 4 weeks) is recommended, but the product will not clear a completely blocked pipe."

I'm reluctant to take off every rad on this microbore system in case I end up with a load of leaks when I put them back, especially since all the rads are now heating up nicely. When I flushed out the X400, the water was quite clear, with a orange tint in it, though the filter had picked up quite a bit of sludge. Having read some other stories about using cleaner in the hell that is microbore, i'm worried that any more cleaning chemical could dislodge sludge and cause a blockage again

What do you think about the idea of fitting the new pump and running the heating for a few hours every day and then cleaning the sludge from the filter every day to try to gradually clean the system? Or is this just a stupid idea that will result in a failed pump?

 

[Circuital]

I'm now also thinking about giving the system a quick blast of Sentinel X800 befor I fit the new pump but as above, do people think it's worth it considering the rads are all working again? The only reason I'd be doing it is to preserve the new pump.

I'm hoping to get this sorted today so would be really grateful for any advice

 

[rhinosaw]

I wouldn't worry too much about your new pump, it will be fine.
Your system sounds a lot cleaner than my old vented system. My Grundfos pump is still ok after 20 years use.
Makes sense what u are saying about cleaning the filter to get rid of residue gunge, having said that I'm no expert

 

[Harry Bloomfield]

What do you think about the idea of fitting the new pump and running the heating for a few hours every day and then cleaning the sludge from the filter every day to try to gradually clean the system? Or is this just a stupid idea that will result in a failed pump?

Motman's method is logically the better way, pumping through one rad at a time. If it's really bad, flush out several times. My system is 35+ years old, has had inhibitor in constantly since new, during which time it is on its now third boiler, second pump (unnecessary). Last time around, I decided to replace the galv F&E tank with a new plastic one. Each time it had a new boiler, I simply gave it a good flush through with plain water, after using full speed pump, one rad at a time. Very little came out of it and none during the most recent boiler swap. Last time (March 2018), I added a magnetic filter, which I have cleaned out four times since then, the amount it is collecting is negligible. I gave the system a check over and service last week and nothing at all came out of the filter, clean as a whistle.

What you have not explained is why you intend fitting a new pump - is it noisy, leaking?

If neither, then leave the old one in place until it needs to be swapped. Just keep its replacement to hand if you already have it. If the filter is collecting a lot, then clean it often.

 

[ianmcd]

Do not use X800 if you dont get it all out your new pump will suffer, X800 is far too aggressive and eats pump bearings for fun

 

[Circuital]

Thanks for all the replies. I wanted to change the pump because it is noisy as hell. I imagine this was because it was constantly trying to work through all the ****e running through the pipes.

@ianmcd thanks for the technical advice regarding the X800. I rang the technical line at Sentinel this morning and I got the impression it's run by sales staff, not experts, as they just gave me general advice that's already available on the instructions!

I'll try to make some time to clean each of the rads or get someone to do it for me.

 

[JohnD]

X400 loosens the dirt. Draining will get some of it out (never all of it)

If you can afford £100 or so more, you can add a system filter such as a Magnaclean, which will eventually trap whatever remaining dirt is still circulating, before it has time to settle into sediment and new blockages.

You'll find, if you empty the filter regularly, that it captures quite a lot at first, and then over time the amount reduces, as there is less and less remaining in the system.

Without adding a cleaner such as X400, a lot of the dirt will just sit in the system. Plain water flush will only remove some of the loose stuff.

 

[SpecialK]

Pull the pump to bits - The impeller is probably full of little balls of crud that rattle around when the pump is on... Make sure you clean out the flutes in the impeller too....

Thanks for all the replies. I wanted to change the pump because it is noisy as hell. I imagine this was because it was constantly trying to work through all the ****e running through the pipes.

@ianmcd thanks for the technical advice regarding the X800. I rang the technical line at Sentinel this morning and I got the impression it's run by sales staff, not experts, as they just gave me general advice that's already available on the instructions!

I'll try to make some time to clean each of the rads or get someone to do it for me.

 

[Circuital]

Well I spent ages cleaning the pump yesterday and when I re-fitted it, it kept tripping the RCD, so massive DIY success from me there! I think I probably got some of the electrics wet, like an idiot.

In a calculated, prolonged fit of rage, I went ahead and fitted the new pump which annoyed me further because the direction of the flow on the pump meant that I had to install it upside down (i.e. the writing on the label is upside down), although from my research, this shouldn't be a problem. I also bailed out the F&E tank, drained down and flushed the system, and then added two litres of X400 upon re-filling.

The heating now works perfectly and the pump is quiet, for the time being. I'll keep it running for a few hours each morning and evening and use a rubber mallet to gently tap the rads and any exposed pipework and clean the filter (it's an Intaklean 2) twice a day, for the next few weeks, before draining and flushing the system again. I'll let you know about my results. Thanks to you all for your time again.

 

[JohnD]

if you turn the heat on the boiler down or off, you can run the pump all day without using any gas.

you will have to turn the CH off and the boiler up when you want hot water, though.

 

[ianmcd]

In a calculated, prolonged fit of rage, I went ahead and fitted the new pump which annoyed me further because the direction of the flow on the pump meant that I had to install it upside down (i.e. the writing on the label is upside down)

wont make any difference to the pump but if it bothers you, when you drain it down again, undo the Allen bolts totate the head so the writing is the correct way up and then put the Allen bolts back in and tighten them

 

[Circuital]

if you turn the heat on the boiler down or off, you can run the pump all day without using any gas.

you will have to turn the CH off and the boiler up when you want hot water, though.

Hi JohnD,

Will this still help to free the sludge? Is the cleaner not more effective at higher heat levels to dislodge the sludge?

Cheers

 

[JohnD]

I have an idea that it is, but I think the extra hours of circulation will help. The instructions do say "preferably" at normal operating temperatures. As you have a filter, the longer it circulates, the more particles will be caught (twice a day sounds excessive though). They don't catch everything on the first pass.

"To clean an older system in accordance with BS 7593, this product should be circulated (preferably at normal operating temperature, with all valves open and the pump turned to maximum flow) for a minimum period of 2 hours or until satisfactory performance is restored. Use in conjunction with a powerflushing device to achieve a more rapid clean.

Where systems are badly fouled, we recommend a longer circulation period (approximately 3-4 weeks). The product is not aggressive and can be safely left in the system for extended periods."