The first thing I must say is that I had nothing to do with the installation of this system.
My customer has a system comprising of a pair of Greenstar 24Ri boilers plumbed in cascade, on an open vent system. The circuit is. for want of a better description, like a very large bungalow; with a maximum head of less than 3metres. There are 20 radiators on the heating circuit, all fed off drops on a circuit loop of about 60 metres. The pump, which is situated just 1.2 metres below the base of the F&E cistern is a Grundfos UPSD 40-80 F 250, which I think is way too powerful.
The customer has reported to me that they have replaced many radiators due to rusting. When I have observed the system the circuit water is circulating rapidly through the F&E cistern, leading I believe to excessive oxygen entrainment and consequent rusting. There is no low loss header fitted.
What would be the best thing to do with this mess, with consideration given to the fact that a complete refit is out of the question. There is no possibility of increasing the available head. My initial thoughts are to convert the system to a sealed system, but I would value the help of people here, some of whom seem very expereienced with this type of set-up.
My customer has a system comprising of a pair of Greenstar 24Ri boilers plumbed in cascade, on an open vent system. The circuit is. for want of a better description, like a very large bungalow; with a maximum head of less than 3metres. There are 20 radiators on the heating circuit, all fed off drops on a circuit loop of about 60 metres. The pump, which is situated just 1.2 metres below the base of the F&E cistern is a Grundfos UPSD 40-80 F 250, which I think is way too powerful.
The customer has reported to me that they have replaced many radiators due to rusting. When I have observed the system the circuit water is circulating rapidly through the F&E cistern, leading I believe to excessive oxygen entrainment and consequent rusting. There is no low loss header fitted.
What would be the best thing to do with this mess, with consideration given to the fact that a complete refit is out of the question. There is no possibility of increasing the available head. My initial thoughts are to convert the system to a sealed system, but I would value the help of people here, some of whom seem very expereienced with this type of set-up.