Ferroli Modena not working for DHW or CH, please help!

[Ashlioct]

I could really do with the benefit of somebody's expertise...



My CH system was drained and the rads removed when plastering about 2 months ago. They were replaced and the system filled back up by someone not very qualified who nevertheless seemed to know what he was doing, and the CH and HW have been working ok since then, but I have hardly had to put the CH on until now.

A few days ago I put on an upstairs rad which had not been turned on until now and that seems to have bu@@ered it up...if I turn the HW or CH on the pilots lights and the boiler fires up but clicks off again a few seconds/ minutes later with the light flashing to say there is insufficient pressure in the CH system. It then won't click back on for half an hour or so.

The actual boiler pressure is nearly 2 bar. It drops a few points when the boiler clicks off but never below about 1.7 bar. The longer you leave the boiler idle for, the longer it will stay on when you call for CH or HW, but never more than a few minutes at a time....not long enough to get anything warm!!!


I have.....

Bled all the rads of air
Opened the auto air valve and emptied the pump of air
Loosened the big screw on the front of the pump
Checked all the wires are clean and connected

And now I am fresh out of ideas. It is a Ferroli Modena 80 E and the documentation I have states it is six years old.

 

[Agile]

I am guessing but it sounds as if the pressure gauge is telling lies!

When the system was drained did the gauge go down to zero?

Could you pressurise it to 0.5 Bar ABOVE the current pressure and see if that makes any difference.

Also check that both the heating valves under the boiler are in the on position.

Tony

 

[Ashlioct]

I'm not sure if the gauge went down to zero when the system was emptied. All the taps are open.


Interesting...I have just raised the pressure to about 2.5 bar and tried to fire up the CH. Pressure rose to about 2.8 or 9. Same thing happened, except that the light isn't flashing to say insufficient pressure in CH system anymore. So sufficient pressure, but it still cut out in a few seconds.


Is this progress? I'm not sure!! Any more ideas please?

 

[gas_man_gaz]

or it could be a blocked low water pressue switch?

 

[gas_man_gaz]

by the sounds of it u'll be changing the prv soon!

 

[Ashlioct]

Is there anything else I can try? Or am I in need of an engineer?

 

[mehran]

your system is most likely dirty, that model of boiler will fire up even tho the low pressure switch is open for a few seconds then switch off

you need a new low pressure switch and a clean system

 

[Ashlioct]

Thanks, I will call in a professional. If anyone else has any ideas I would be happy to hear them.