N
noonespecial
Surely he hasn't mentioned cost because it is his fault. 
Make sure you check that he is doing it at his own cost though.
The system should have been correctly chemically flushed though before he fitted the boiler. If the installer is competent and experienced - he knows what should have been done and what the risks were if he didn't do it.
Also the inhibitor has to be suitable for aluminium, copper and steel and any other materials you may have in the system.
I think as well with existing systems that a strainer on the return to the boiler is a very good idea as an additional safeguard to protect the boiler. Some of the boiler manufacturers recommend that one should be fitted but not Baxi. If one is fitted , it is esential that it is regularly cleaned out.
But alarm bells are also ringing in my head as it is an existing system- check the pipe sizes from the boiler, find out what the pressure drop though the boiler is and at what temperature drop the pressure drop is measured at and also what the pump model is and come back. If you have not got the boiler installtion instructions you can get the pressure drop info from Baxi or someone else on the forum may be able to advise?
You may also have another problem lurking. You have re-used the existing radiators which would have probably been designed for an 11 deg.C temperature drop. You may find that this boiler will only be able to operate at 20 degC temperature drop (because of the boiler pressure drop) in which case your existing radiators may now be undersized for your heating requirements
Make sure you check that he is doing it at his own cost though.The system should have been correctly chemically flushed though before he fitted the boiler. If the installer is competent and experienced - he knows what should have been done and what the risks were if he didn't do it.
Also the inhibitor has to be suitable for aluminium, copper and steel and any other materials you may have in the system.
I think as well with existing systems that a strainer on the return to the boiler is a very good idea as an additional safeguard to protect the boiler. Some of the boiler manufacturers recommend that one should be fitted but not Baxi. If one is fitted , it is esential that it is regularly cleaned out.
But alarm bells are also ringing in my head as it is an existing system- check the pipe sizes from the boiler, find out what the pressure drop though the boiler is and at what temperature drop the pressure drop is measured at and also what the pump model is and come back. If you have not got the boiler installtion instructions you can get the pressure drop info from Baxi or someone else on the forum may be able to advise?
You may also have another problem lurking. You have re-used the existing radiators which would have probably been designed for an 11 deg.C temperature drop. You may find that this boiler will only be able to operate at 20 degC temperature drop (because of the boiler pressure drop) in which case your existing radiators may now be undersized for your heating requirements
