would this work

Paul S_3

The pic below shows a job that i am correcting due to pipe size. I will be increasing pipe size from 3/4 to 1 1/4". Pipe size from boiler and indirect is 3/4...and boiler is piped incorrectly.There is a existing laars minitherm 160. I will be keeping the 4 way (1 1/4) "dumb" mixing valve with the zone valves and pump on the system side. I will be installing new indirect on priority and repiping boiler. The laars boiler recommends a bypass or a primary secondary setup. If i us the primary secondary setup would i have to use an extra pump on the boiler side of the 4way valve?Would this setup work? Any other suggestions will be appreciated thanks

Paul S_3

Or would this be a better setup? Primary secondary

hot_rod

A hydraulic separator would be another option. It would give you separation, air, dirt, and magnetic in one device.

The 4 way without an actuator and control neither gives you boiler protection or accurate temperature mixing, it's just a guess as to where in needs to be set and adjusted. With a non-con you need some sort of boiler protection.

Does the boiler show any signs of running too cold? Inspect the heat exchanger carefully, it may be on borrowed time.

STEVEusaPA

@hot rod Hey Bob, quick question, even though both circs have flow checks, does pointing them at each other have any potential maintenance/failure issues-long term? Just wondering

Paul S_3

Hot rod....i understand what you are saying....but would both my drawings work? I put in a quote for tekmar 360 with act motor setup.....the boiler does have signs of sustained flue gas condensation...all of the zones are lo temp radiant....and would a bypass or primary secondary help with this?

hot_rod

better? From an old PM Engineering article

hot_rod

STEVEusaPA said:

@hot rod Hey Bob, quick question, even though both circs have flow checks, does pointing them at each other have any potential maintenance/failure issues-long term? Just wondering

I don't think so if only one runs at a time.

Paul S_3

Yes...thanks hot rod....but i will have the indirect pump pumping towards the tank

hot_rod

Paul S said:

Yes...thanks hot rod....but i will have the indirect pump pumping towards the tank

In your drawing, I'm not sure you need 4 pumps? The primary loop circ and system circ are in series, the more the 4 way opens, the more you are moving to doubling head.

Assure the boiler gets proper flow with that circ selection, I think the system pump should be enough for the radiant and loop it connects to.

I'm still pushing for the sep

I like the indirect on the primary side of the sep, or loop, as you have it. If you want both indirect and radiant circs on the secondary, a check would be wise to prevent flow potential thru a "off" radiant zone.

There are a number of way to pipe this, I like a simple, multi-tasking component (sep) approach.

If the indirect can handle the full boiler output, circs properly sized, there would be minimal temperature blending in the sep.

Aaron_in_Maine

Instead of a sep if you have small micro zones maybe a buffer tank as a sep to keep the boiler from short cycling. Don't know what you have just spit balling.

Paul S_3

Thank you guys much appreciate it ....im goin with the sep4

unclejohn

Who tried to read the backwards writing at the top of the page.