Heat exchanger overheats

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
sengcy
Posts: 4
Joined: 10 years ago

#1: Post by sengcy »

I owned a used heat exchanger for about 6 months. 3 weeks back, it suddenly stopped heating up. I traced the problem to a blown thermal fuse. After replacing the fuse, it was working fine. I did not put the cover back on until last weekend. With the cover back on, the fuse has blown again. Fortunately, I bought a few spares. Once again, the machine is working fine without the cover. Somehow, the machine is trapping a lot of heat.

Some additional info:
1) Machine - Isomac. I'm not sure which model, since I'm not the original owner. Guessing from photos on the Internet, my guess is it is a Rituale, but I don't think the exact model matters here.
2) Prior to this incident, I had replaced the pressure stat (sticky pressure stat issue). The pressure range between 0.9 to 1.1. I think this is a reasonable range.

I'm thinking that the water level in the boiler may be too low. Perhaps the level probe needs a little adjustment. If this is the case, I'm not sure why it worked for the past few months. Does anyone have any other ideas? Thanks.

User avatar
cannonfodder
Team HB
Posts: 10497
Joined: 19 years ago

#2: Post by cannonfodder »

The obvious first question is what thermal fuse (rating and or color is the fuse) and how is it mounted?
Dave Stephens

sengcy (original poster)
Posts: 4
Joined: 10 years ago

#3: Post by sengcy (original poster) »

Hi Dave,

The rating is 167C. I mounted it as shown in the picture. Thanks.

Mike_
Posts: 29
Joined: 16 years ago

#4: Post by Mike_ »

Do you have a boiler pressure gauge and if so what is it reading? If not, have you tried adjusting the pressurestat?