I have a loud whooshing noise in my radiators. If i turn pump down the noise in my radiators disappears but when i run hot water for a bath the boiler overheats & cuts out and water runs cold after a while until it is relit. Would it work if i fit an automatic pump and would it then have slower speed for c/h & faster speed when running the water. If this is the answer then i will gat a new pump but i do not want to go to this expense if it wont work.