New homeowner considering self-install

Chatham

Hello,

I've been lurking here for a while and getting a a handle on what to expect as I update the original heating system in my 75 year old home. The House is 1000sf with a full basement and of brick sheathed lumber construction. The main floor is heated by the original coal boiler which was at some point converted to oil and then to gas with a 200,000btu burner. It feeds 7 radiators with a combined output of around 45,000btu. The basement is split between shop/utility space and a Mother-in-Law and heated by a very old gas space-heater in addition to the heat of the boiler and its gravity fed piping.



I have already removed the original galvanized piping, which was rusting through and have started to replace those runs with 1/2" ThermaPEX, one loop per radiator. I plan to remove a few of the radiators that are in akward places and move them downstairs while adding Ultra-Fin radiant panels while I have access to the joist bays.



I have tried to do a few heat loss calculations, but without knowing more about the insulation situation inside the walls I have had to make some educated guesses. I am coming up with a fairly conservative guess of around 37,000btu/h; does this sound in the right ballpark for a small 1930's house in the mild climate of Seattle?



My current plan is to move to a mod-con boiler with the option of an indirect tank in a year or two while also leaving enough overhead for a small attic addition further down the road.



Here is the list of the products I'd like to install:

Boiler: Rinnai Q85SN

Manifold: 2 x Rifeng 5-loop with meters and valves(one for radiant floor, 1 for rads)

Circulator Pump: 2 x Taco 008 delta T variable speed(1 per manifold)



Would anybody have other recommendations on a project of this sort?

I am definitely at least going to do the tubing work myself and would like to handle some of the boiler install myself as well. Is this a terrible idea?

Does anyone sell very small indirect tanks? The smallest I have found is 29 gallons.



I am not adverse to spending the money to hire someone to handle the job but I enjoy doing it myself and knowing exactly how and why each component is functioning and if I can save a little money without botching the job I like that too.

CMadatMe

Like the Approach

I like your approach but not a fan of high temp radiant systems. I gather your boiler would be your mxing valve that controls temp for both the rads and the radiant? If your willing to spend some money then suggest you hire a pro to help with the heat loss, design and firing off of the boiler. Personally don't have issue with a do it yourself project providing a pro fires, wires and inspects.

Chatham

Thanks for the response,

I assume you don't like to run the radiant systems hot because it negates the use of a condensing boiler?



I had assumed that with the outdoor reset the system will ramp the water temperature as high as it needs too for the circumstances(assuming it is set correctly) allowing it to stay condensing except on the coldest nights?



I would like to run the whole system at a lower temperature and make up the loss of output from the radiators with the added floor heating(as well as storm windows and general tightening up of a very drafty house). I've been hoping to experiment a little over the winter before I seal up the ceiling.



I also had considered running the in-floor in series from the radiator return lines, but this seems pretty out of the ordinary and I assume it would cause trouble with large temperature differentials shocking the boiler.





I will absolutely at least have a professional inspect and fire the system and it is looking like I should consult with someone to make sure my calculations are in order.

Gordy

Many questions to ask

Yourself. Once you have done a heatload calc.

You speak of tightening up the envelope in your post. Question: How far are you going to take it?  You need to answer this because the boiler you size now will be to big if you really tighten things up. But then if your calcs are correct its not a big load to begin with.



Apparantley the old system heated the dwelling before. You speak of adding radiant floor heat.  Question: Is the radiant floor heat going to be for floor warming only? Or do you intend to try to heat the space? Which brings another question: Where you intend on installing RFH what floor coverings do you have in mind?



Gordy