Buderus Radiators

homeimprovement

Hi guys. This is my first time using this forum, so apologies if this topic already covered elsewhere. I'm a homeowner who recently purchased a 100 + year old home in North East. It has hot water cast iron radiators and oil boiler. I had a new Buderus boiler installed last year (G115WS). System worked great until we tried, as part of a house reno, to replace several of the cast radiators with Buderus Model 21's. We cannot get them to heat up despite rest of the system working. Flushed them a bunch of times. The system is a multiple one pipe system with home run supply and return lines to old pipe loops in basement. Heating lines to all radiators are new 3/4" PEX. We installed 1/2" compression fittings on the Model 21's per the bosch specs for the units. I purchased thermostatic sensors but not installed yet. The circulator pump is whatever comes with the G115WS and is turned to the highest setting. I spoke to the vendor (supplyhouse.com) who speculates that I need a higher powered circulator pump but that makes no sense to me as the boiler is new. Any help you can provide would be much appreciated.

many thanks.

Alan (California Radiant) Forbes

When you flushed the system, were you able to do it one radiator at a time?
Can you send us some pictures showing the piping at the boiler?

homeimprovement

Thanks. Yes. Will send pics.

Charlie from wmass

Water takes the path of least resistance. Those radiators offer and exponentially higher level of resistance then a cast iron radiator. What method are you using to balance the flow between the different radiators?

homeimprovement

Nothing right now. I have big 4" asbestos supply pipes in basement and unable to install Venturi tees off that main line to these units. Hoping for another method to get flow to them that isn't too complicated and costly. Thanks.

Charlie from wmass

That means that you had a gravity not a forced hot water system. The restrictive path of the buderus radiators is not going to like that.

Ironman

The new rads will require a separate loop, circ, etc.

I'd recommend that you get a HYDRONICS pro. You're in over your head.

Try the contractor locator on site.

Timothy77

Hey, sounds involved. I'm also north eastern ny if you're close by I would be happy to check it out.

Timothy77

You probably are going to need to change your piping configuration. Not trying to make you nervous,but that a lot of Valium for one circulator(depending on its size).

Charlie from wmass

Volume?

Timothy77

4" supplies with factory circ.

Charlie from wmass

You wrote valium. Lol

Timothy77

Yup,hilarious.

Timothy77

Homeimpovement, I hope you keep us updated on the repair. Whichever way you decide to go .

homeimprovement

Thanks all. Will do. Time to bring in a pro.

Charlie from wmass

Where are you located?