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Joined on January 19, 2012

Last Post on July 21, 2014

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@ June 26, 2014 8:19 AM in need electrical help

Unless you are installing external safety devices, the boiler is pre wired to handle all that.
Anytime the connection from R to G is made, the boiler will fire.
For the one zone system the t-stat can be wired to R and G.
For 2 zones, I would use a taco zvc403-4


@ June 26, 2014 7:50 AM in need electrical help

Zone valves? Single circ?
I think the taco control relays really clean up and simplify the low voltage side.


@ June 26, 2014 7:27 AM in Wood with mod/con. Piping help please

Here is a good read on the subject.

The points I would be most aware of is the need for a buffer tank and if the boiler is going to be in the house, a good thermal bypass loop.

You cannot just shut off a wood boiler the potential for overheating is huge.

The expansion tank location in the manual is incorrect.



@ June 24, 2014 10:06 PM in Need to replace big old galvanized pipe with pex

I agree with jstar, you have to do the math.
How is the piping being run? Is this a reverse return system?
Take your time and do this right. There are far too many folks using rules of thumb and guessing.

Flow rate

@ June 24, 2014 9:57 PM in Initial target Flow Rate calculations

First off, you do not need 2fps with a continuos pex loop. It will easily purge air at 1/2 that.

I do think you will have trouble balancing a system as out of balance as yours will flow rate alone.i also think you are likely to have air issues at .1 gpm.

Is it possible to put trvs on in the areas that are over radiated.


@ June 24, 2014 6:38 AM in how prevalent is this?

You realize this article is 25 years old?
Much has been learned since....


@ June 21, 2014 12:39 AM in Hot water first floor, luke warm water second floor

Air would make sense if you had hot water after waiting for it.
Diagnose the problem, don't just guess.

Narrow it down.

@ June 20, 2014 9:38 PM in Hot water first floor, luke warm water second floor

First, do you have a water production problem or a cross connect problem?
Is the piping at the heater hot when you are having the problem? If so, you have a cross connect.
To eliminate the recirc loop as a culprit, turn off the circ and close the purge valve below it (you will have to find the handle or turn it 90 degrees with a wrench.)
If that is not the cause, keep looking. Sometime the best tool is just feeling the pipes around the house until you find something that doesn't make sense.


@ June 20, 2014 11:56 AM in Hot water first floor, luke warm water second floor

I think a picture of the circ pump piping would help...

Cross Connect

@ June 20, 2014 8:44 AM in Hot water first floor, luke warm water second floor

It i quite possible this has nothing to do with the Navien.
If you have a connection between hot and cold anywhere in the house, it can cause the problem you are having. Common causes are a hose "Y' going from hot to cold on a faucet. It could also be caused by a shower head shutoff valve or faulty appliance like a washing machine. What has changed?


@ June 20, 2014 12:01 AM in TT Smart 80 & Prestige Solo 110 Summer Gas Usage

Your mixing valve is not bringing in cold water and reinjecting it in the tank. I couldn't because it would have to somehow displace the hot water. What it does is, circulates the 120 water and then mixes in 140 as needed.
As mentioned, insulating the line would be the best first step.
I like a combination of time and aquastat control on recircs.
Over sized and over used recirc pumps can also cause pipe failure.
Pictures are always nice.

Boiler replacement

@ June 19, 2014 10:57 AM in 95% Efficient Condensing Replacement Boiler

If you wants really good advise, start a new thread and post all the pertinent info.
Here is a good example

This post has almost nothing today with your project. It has turned into a debate about at least a half dozen unrelated subjects..


@ June 19, 2014 10:49 AM in Typical venting for high-efficiency wall-hung boilers?

I don't see a need for bigger than 3". Unless you have very long runs(over 60') or a very large boiler(over 250k). 3" is more than enough.
Polypro is going to be the standard soon. The code they are a changing, don't get caught with the wrong product in the future.
The intake can be PVC.

One post wonder...

@ June 17, 2014 2:13 PM in 95% Efficient Condensing Replacement Boiler

This is a one post wonder who tacked a question onto an unrelated old post.
I'm with Rob on this one. How in the world could you come up with any recommendation with the info that was given?
Heat loss?
DHW needs?
Must be a slow day...

Slow down

@ June 4, 2014 9:31 AM in Reconnect oil boiler after copper ransack

You are are correct that you have 2 separate water circuits in the boiler. You are incorrect in thinking you can fire the boiler with just the domestic side hooked up.
The domestic coil is submerged in the heating circuits water. The entire system needs to be hooked up in order to fire the system.

Have you pressure tested yet?

I would suggest pressure testing the boiler first to find out if this boiler is worth the effort. You don't need to test the domestic coil, if it leaks you will see it when you test the boiler.

Once you have determined if the boiler is good, post your proposed piping diagram on here for feedback.

You should really make sure you have wrapped your head around the key safety elements in a boiler system. Failure to correctly install the pressure relief valve or low water cutoff can result in a major explosion (see mythbusters).

Incorrectly venting are tuning can result in carbon monoxide poisoning (death).

From what I have seen in your posts so far, you don't seem to understand the job at hand.

An incorrectly installed boiler really can kill you.

Aside from...

@ June 4, 2014 8:56 AM in Noisy pump

Aside from the obvious, get the circulator out of the dirt and support the piping properly.
I think it is likely that the noise you are hearing is coming from the mixing valve. Those are really designed for domestic hot water systems and tend to make a noise that sounds like a small nail is stuck in the pipe. Changing the pump speed may help as may proper pipe support.


@ June 1, 2014 6:18 PM in Variable Speed pump control issue

The manual attached is for a relay module. Do you have a manual for the Geni?
0-10 VDC is usually just 2 wires or 2 wire and a ground. The voltage varies from 2-10 volts DC. The solar controller would be putting out the signal and the Geni module would receive it and ramp the circ up and down accordingly.
We would need the manual to be more helpful.

Crevice corrosion

@ June 1, 2014 8:31 AM in Rinnai boiler corroded in less than two years

I think Ice is on it.
The combination of O2 and the low PH makes crevice corrosion seem very likely.
Combine that with the fact that most of the damage is around welds and gasketed connections with dissimilar metals and I think the cuprit is pretty clear.

I am guessing this is not the first boiler this house has had. What happened to the previous on?  How was the system purged when this boiler was installed? You likely have a bad "cocktail" that is, in part, made up of the ferrous components of " boiler past"

Heat Generator

@ May 29, 2014 2:37 PM in Boylston device

That looks like part of an old heat generator. The part with the mercury has been removed. They were ingenius devices that allowed gravity systems to run at temperatures above the boiling point and still be a safe nonpressurized system.

Heat Load

@ May 29, 2014 12:17 AM in Heat load calc( to pay, or not to pay)

I have to agree with NBC on this one.
My experience with Engineers on heat loss calcs is, they round up, Big.
Unless you have a high level of confidence in the guy you are hiring, do it yourself.
Siegenthaler has great software on his site that make the process pretty foolproof. The biggest unknown is the air change rate. Without a blower door test, everyone is guessing on that one.


How I (Almost) Saved the Earth

@ May 29, 2014 12:03 AM in How I (Almost) Saved the Earth

There was a question about picking the right Engineer on another post that reminded my of this article from a while back.
Funny, Funny Stuff!


@ May 27, 2014 11:23 PM in Time for an upgrade/retrofit

I am not sure I am following your thoughts.
I would have no reservations using a triangle tube prestige or a WM 97 firetube model.
Either could be piped without primary secondary as you suggest with no issue.
The existing piping likely holds hundreds of gallons, not to mention the piping and rads.
A good dirt separator is essential with an old gravity system.
As for the DHW, if there is space for an indirect tank, that would be my personal preference.
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