Slant Fin VGH150

Peterug13

Have a VGH-150 about 5 years old with DHW. The boiler pressure was increasing past 30 pounds making the relief valve drip. I assumed (because our water quality sucks) that Watts fill was gunked up and water was seeping by. After replacing it and the boiler side relief valve I noticed the pressure was still climbing in the boiler and after about 15 mins the RV would start weeping again. I turned off the DHW water feed, bled the excess pressure and its held at 15 pounds for several hours. Tells me that the DHW plate HX is bad. Ive never worked on one of these and just want to see if there is anything else in this particular boiler that might cause/contribute to that.

Thanks!

mattmia2

the tankless coil is bad if the pressure stops creeping up if you turn off the water to the tankless coil.

is it steam or hot water? not sure if anyone still has the coil or the blank off plate since slant fin is out of business. you could replace it with an indirect but a separate gas or electric or oil water heater might be your best bet. tankless coils have a ton of standby losses anyhow.

Peterug13

its hot water….it's a condensing boiler with a plate exchanger…. i actually have a few of the blanking plates for the cast iron boilers brand new kicking around it you ever need one.

I figured its pretty much the same as a CI with a tankless coil. I just did one of those coils the other day,,,,,what a pain in the ****.

mattmia2

oh, it is a mod con combi. maybe you can get the hx from a distributor or fit another hx in there.

GGross

these guys have the OEM plate heat exchanger, still a few left.

https://www.parts4heating.com/product-p/817298000.htm

Peterug13

Thanks!