Need nuts and bolts help

Alan(CaliforniaRadiant)Forbes

explain the near-boiler piping. If you look at the picture working from the bottom up and pulling off the primary loop, there's a Taco mixing valve for the basement slab (no outdoor reset), a supply and return for the 2nd and 3rd floor radiators (green pump, no outdoor reset) and on top is the injection system for the 1st floor staple-up (brown pump, with outdoor reset).

We installed this system in 2002 and it's been flawless (knock on wood).

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riethoven

Specifing parts and building a new system

I am a homeowner with a gravity hot water system with both cast radiators, and Euro flat panel radiators. I also want to add some radiant, and domestic hot water. The boiler is a WM 663 with 130K BTU. I used the fintube software and came up with a heat loss of 48K BTU. I purchased the I=B=R workbook and have determined that primary/secondary will work the best for me with all the different types of loads. I have a few questions regarding the building of the new system.

1. I want to use oxygen barrier PEX to replace the 3/4" and 1" black pipe that go to and from the radiators. These lines would go into a manifold that would be a secondary loop. Have people done this? I know it will be alot quicker to run than copper.

2. My boiler is from 1961 and is cast iron. I have been unsuccesful in getting any information out of WM so I will ask you. What is a safe minimum return temperature?

3. A picture is worth a thousand words. Does anyone have photos they can post of some of the hardware they have used on a system like this? As I mentioned I want to do a primary secondary loop with individual pipes to and from each radiator which go into a manifold. This way, I can precisely control the flow to each radiator.

Since I am a homeowner, I have a steep learning curve. I am sure that I will have more questions as the system progresses.

Thank You

Alan(CaliforniaRadiant)Forbes

Gravity conversion

Some answers to your questions:

1) Yes, we've used PEX for individual radiator piping out of a manifold. Just make sure you protect your tubing from a runaway boiler.

2) 130 degree return temperature is minimum. If you use an injection syetem, specifically a Taco PC 705, you can set it up to automatically protect your boiler.

3) See attached pictures of an injection system we did in SF.

You should also install thermostatic radiator valves at each radiator to balance your old gravity system, otherwise you may get uneven heating.

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riethoven

Near boiler piping and outdoor resets

First of all thank you for your great response. I know that I am kind of going at this in the dark because of my lack of experience, but paying someone to do it just was not in the budget, and the three heating people that I approached didn't know what I was talking about when I mentioned primary secondary piping.

Does your primary loop go through the boiler? All the IBR diagrams on primary secondary show the boiler as one of the secondary loops.

I thought that an outside reset was for the boiler, not for each zone. How does that work?

You mentioned that I should put thermostatic valves on each radiator to avoid cold spots. If I have a ball valve at the manifold for each radiator, can't I control flow at that point and therefore balance that zone, and not need the thermostatic valve?

Alan(CaliforniaRadiant)Forbes

Some articles

for you to read:

Primary-Secondary piping:
http://www.pmengineer.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2732,2755,00.html

also:
http://www.pmengineer.com/CDA/Archives/364755c9ff298010VgnVCM100000f932a8c0____

Outdoor reset:
http://www.pmengineer.com/CDA/Archives/cdd55d5472298010VgnVCM100000f932a8c0____

And as far as balancing the system, ball valves won't do; your large volume heating system will want to heat the radiators closest to the boiler first; as these rooms warm up, the thermostatic radiator valves (TRV's) will reduce the flow to the radiators in the warm rooms, allowing water to flow to radiators in the rooms that are still cold.

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