Ideal ISAR Boiler - Pressure rising above 3 bar & leakin

[gardenersweekly]

Hi can anyone help me with a problem with my IDEAL ISAR HE30 boiler.

When CH is on pressure on gauge rises to above 3 bar within 15mins & then leaks via PRV & out thru pipe outside, needing to refill to 1bar when cold. So far had 2 different engineers, 1st said faulty pressure gauge, then he said expansion vessel which he then changed.

Problem still existed, so he suggested power flush of CH system as there is a blockage somewhere. I didnt agree, as all rads & pipework get hot & so does all pipework.
As under insurance they refused to assist any further. So I called another engineer who stated that PRV was leaking even when pressure had only reached 2bar, so he replaced PRV which he said old PRV was faulty. He left system working but had turned down CH thermostat on boiler, so heating was not warm enough. I turned up dial, & problem is still the same.

Since, I have noticed that from system being cold, when turning on HW, CH flow pipe from boiler immediately gets hot & so does flow pipe on nearest radiator.

Finally, this morning, boiler was showing error code L alternating with F, so no HW or CH. Pressed reset button, worked briefly, so tried again and has since been error code free, but with same rising pressure etc.

Can anyone please help/suggest what could be wrong, as this saga started 7 weeks ago.

Thanks in advance

 

[gigz]

Since, I have noticed that from system being cold, when turning on HW, CH flow pipe from boiler immediately gets hot & so does flow pipe on nearest radiator.
Finally, this morning, boiler was showing error code L alternating with F, so no HW or CH. Pressed reset button, worked briefly, so tried again and has since been error code free, but with same rising pressure etc.

The first problem will be a faulty diverter valve/head.
The second one will need a RGI as its a flame detection error.
These are not difficult to diagnose/fix (when your in front of the boiler) Ask about (friends or family) to recommend a good boiler engineer.

 

[gardenersweekly]

thanks for reply, will either of those issues have possibly anything to do with pressure rising?

 

[gardenersweekly]

also 2nd engineer who called out was highly recommended. In last hour another engineer has been out who has no idea why pressure is rising. as you say its not difficult to diagnose when in front of boiler, so why cant any of these engineers see what the problem is. Any advice will be greatly appreciated.

 

[gigz]

Did they check the exp vessel pressure with the boiler drained and drain or vent open ? I know you have had a new one fitted but it could be flat/faulty. Also just because the pipes and rads get hot there could (and i mean could) be a restriction somewhere (doesn't mean you need a power flush though). Did latest engineer sort the LF problem out ?

 

[AVM]

expansion vessel is at fault

 

[Agile]

Just because a new EXV has been fitted it does not mean it has been set up correctly. Some nuptys fit them without setting the air pressure!

I went to an external one fitted by British Gas with an air precharge of 3 Bar. Easy £84 that visit!

But the internal one was not failed ! Just the communication pipe blocked and these can usually be unblocked in 20 min. But you get very dirty and wet if you dont do it properly!

Tony

 

[gardenersweekly]

Did they check the exp vessel pressure with the boiler drained and drain or vent open ? I know you have had a new one fitted but it could be flat/faulty. Also just because the pipes and rads get hot there could (and i mean could) be a restriction somewhere (doesn't mean you need a power flush though). Did latest engineer sort the LF problem out ?


Thanks for reply. Eng who fitted new vessel, I have no idea whether he set pressure correct when fitting. When he came back to check it on another visit he DID NOT drain boiler etc, checked when CH pressure was showing 1bar when cold. He said he charged correctly to about 1 bar. 2nd engineer did the same & said it was charged to 1bar. If they are checking vessel charge in this way what does this mean? Would pressure reading be different, if done right way, would it be lower or higher?

Regarding pipes/rads where 'could' there be a restriction? In boiler?

Latest engineer started boiler a couple of times & didnt get LF error code, so didnt do anything. Boiler not shown code since either, but still pressure issue.

 

[gardenersweekly]

But the internal one was not failed ! Just the communication pipe blocked and these can usually be unblocked in 20 min. But you get very dirty and wet if you don't do it properly!

Is this the pipe from expansion vessel you mean. If so 1st engineer said he cleaned it when he had boiler removed? But I have serious doubts he did as he didnt bother to replace PRV which was leaking at 2bar pressure. 2nd engineer looked at this pipe from one end (end not attached to vessel) and he said it looked dirty/clogged up & tried blowing/sucking on it to clear it! Would this really clean pipe all the way to vessel if blocked?

 

[gardenersweekly]

Would it be good idea to change pipe attached to expansion vessel & check its pressure with boiler drained as next step to resolve rising pressure problem? At the moment getting no error code on boiler and have turned down boiler CH stat to very low, so pressure only rises to 2.5 bar as boiler cuts out, however CH stat is not high enough to heat house. At least this way PRV is not being used and I don't have to keep refilling every time CH is on.

 

[flameport]

When he came back to check it on another visit he DID NOT drain boiler etc, checked when CH pressure was showing 1bar when cold. He said he charged correctly to about 1 bar. 2nd engineer did the same & said it was charged to 1bar. If they are checking vessel charge in this way what does this mean?.

They are just checking the system pressure. This has nothing to do with the expansion vessel at all. The vessel could be empty, overcharged, blocked, busted internally - no way to know.

The ONLY way to properly check the expansion vessel pressure is to have the system pressure at zero (or the vessel disconnected from the rest of the system), then use a pressure gauge on the expansion vessel itself.

 

[gardenersweekly]

Thanks for response. So i don't misunderstand you, the engineers are checking pressure in vessel directly by using gauge on it. They are doing this when system pressure gauge is showing 1bar, ie they have not drained system. Would this mean that pressure reading they are getting is false on expansion vessel, ie showing about 1bar but would actually be less when system drained?

 

[Whitespirit66]

The diagram shows an expansion vessel. The water at bottom is the water in your ch system, pressurised to 1 bar. The air above diaphragm at top is presurised by pumping up through a valve, which you also use to test the pressure in the top.

If the pressurised water at the bottom isn't drained out, then testing the air pressure at the top will give a false reading. In other words, the pressurised water will press on the diaphragm

Untitled

• Whitespirit66
• 11 Dec 2011
• 1

 

[gardenersweekly]

Thanks for diagram & explanation, now understand concept. Will get this checked properly tomorrow. Will update post once done. Cheers.

 

[Temprise]

If youve had this many issues with various engineers, then I would recommend you call Ideal who will do a fixed price repair.

Regards.