I wonder if anyone has come across the following fault in a Ferroli Optimax 38HE combi?
In central heating mode, some 30 seconds after the boiler first starts up, a motor/actuator can be heard to operate for just one second and then, 2 seconds after the motor stops there is often a loud thump/thud/bang. The boiler is in the loft, so the noise transmits as a thump. Inside the loft, the noise is more like the sort of noise you might hear if unburnt gas suddenly catches light - I'm not at all saying that's what the problem is (I really doubt it) but it's a good description of how the noise sounds close up and how different it sounds stood next to the boiler as opposed to on the floor below it.
In DHW mode, a similar thing sometimes occurs but timings are different: a motor/actuator starts only 5 secs after the hot tap is opened and runs for just one second; then, a second or so after it stops running, the thump - if it's going to happen - can be heard.
A few days after this started, the diverting valve stuck in CH mode. A plumber came out and did some investigation but did not remove the diverting valve. He drained some water off and diagnosed a faulty diverting valve. He was going to order a new one, but later I discovered the hot water was back online, so the diverting valve was now working, as was central heating. Nevertheless, the thumping noise is still sometimes occurring.
I don't know if the sticking diverting valve has anything to do with the noise or if it was a coincidence. If it is connected, then the continuation of the noise makes me think the valve may well stick again anytime at all.
Even though the boiler is 2.5 years old, I don't have a great deal of faith in it and am debating replacing it with a Vailant. I don't want to throw good money after bad e.g. paying for a new valve plus fitting only to find another snag etc. On the other hand, if I can identify this noise then I'll be in a better position to make an informed decision.
(Naturally, I've been wondering if that motor/actuator, which runs for a second, is the diverter valve's motor, in which case I'd be a liitle surprised that, in CH mode, a full 30 seconds passes before it operates, and I'd also be a little surpised that the diverter valve motor still runs even if the valve is already in the correct position - although if there is no position feedback, the boiler does not know where the valve is at any time and has to assume it's in the wrong position. If any of this is right, I wonder if the thump is a sticking valve suddenly freeing? However, I have noticed that the noise will occur in CH mode even if no hot tap was opened since the central heating last ran, in which case, unless the diverter valve always parks up in some neutral position, the valve should not have moved since last use?)
I'd really be grateful if anyone can shed light on what this thumping noise is.
Martin
In central heating mode, some 30 seconds after the boiler first starts up, a motor/actuator can be heard to operate for just one second and then, 2 seconds after the motor stops there is often a loud thump/thud/bang. The boiler is in the loft, so the noise transmits as a thump. Inside the loft, the noise is more like the sort of noise you might hear if unburnt gas suddenly catches light - I'm not at all saying that's what the problem is (I really doubt it) but it's a good description of how the noise sounds close up and how different it sounds stood next to the boiler as opposed to on the floor below it.
In DHW mode, a similar thing sometimes occurs but timings are different: a motor/actuator starts only 5 secs after the hot tap is opened and runs for just one second; then, a second or so after it stops running, the thump - if it's going to happen - can be heard.
A few days after this started, the diverting valve stuck in CH mode. A plumber came out and did some investigation but did not remove the diverting valve. He drained some water off and diagnosed a faulty diverting valve. He was going to order a new one, but later I discovered the hot water was back online, so the diverting valve was now working, as was central heating. Nevertheless, the thumping noise is still sometimes occurring.
I don't know if the sticking diverting valve has anything to do with the noise or if it was a coincidence. If it is connected, then the continuation of the noise makes me think the valve may well stick again anytime at all.
Even though the boiler is 2.5 years old, I don't have a great deal of faith in it and am debating replacing it with a Vailant. I don't want to throw good money after bad e.g. paying for a new valve plus fitting only to find another snag etc. On the other hand, if I can identify this noise then I'll be in a better position to make an informed decision.
(Naturally, I've been wondering if that motor/actuator, which runs for a second, is the diverter valve's motor, in which case I'd be a liitle surprised that, in CH mode, a full 30 seconds passes before it operates, and I'd also be a little surpised that the diverter valve motor still runs even if the valve is already in the correct position - although if there is no position feedback, the boiler does not know where the valve is at any time and has to assume it's in the wrong position. If any of this is right, I wonder if the thump is a sticking valve suddenly freeing? However, I have noticed that the noise will occur in CH mode even if no hot tap was opened since the central heating last ran, in which case, unless the diverter valve always parks up in some neutral position, the valve should not have moved since last use?)
I'd really be grateful if anyone can shed light on what this thumping noise is.
Martin
