I have installed a 3 ton Heat Controller unit to replace my 35 yr old oil forced air furnace.  As I had never done this before, I am always looking for recommendations or suggestions from the experts.  I haven't plumbed the HWG yet, but have the unit running since 10/24 and am very satisfied with everything so far except some noise from the water discharge going through the valves.   I am enclosing 3 photos, and would appreciate any advice.
Thanks,
Al 

On the wall, why does the piping branch off and combine back together with seperate shutoff values and slow close values on each branch. What is the purpose of this? Is there a water flow rate indicator anywhere on the system? How can you determine the GPM running thru the system?

 

It is a 2 stage unit, so when it calls for second stage, the other valve opens to let more water throughthe system. Right now I have ball valves for water control, and can measure the amount of flow with a 5 gallon pail at the discharge. I may put fancier flow controllers in though.

not to change the subject to flow rate meters, but coolmccool may want to add one in future, TechGromit, do you (or others) know a source for a fairly inexpensive GPM indicator? I want to include one in my system. Thanks

BTW Coolmccool, nice looking hoses!

Try searching for Hedland 16gpm on Ebay, there are some for $30 that should do if that is enough flow for your system

While not inexpensive, if you have an instrumentation system you want to interface the flow meter to, this is one model of a popular series:

http://www.instrumart.com/Product.aspx?ProductID=10025

If I had to do it over again, I would have had something similar installed into my loop.  As it is now, I don't think it's a trivial matter to install one of these (or for that matter any flow meter) in-line to my HDPE pipe., including loop re-purge considerations and the fact that my loop is at 60 psi statis pressure.

Best regards,

Bill

Thanks Bill and PX - those are both great. I do want a visual indicator so I just went and bought the Hedland transparant flow indicator, price is right. Bill, those 4 - 20 flow meters start at $ 209, so its not out of the question to do that too. I guess if I wanted to track BTUs extracted from the source water, the calc would require it.

In consideration of flow meters be sure not to introduce too much extra restriction to flow. I surfed the link above but did not see the Delta-P imposed by the meter. At the top of its flow range that could be sugnificant

Maybe should be concerned...the meter I'm looking at is about 8 PSID pressure drop at 12 GPM from their chart, the higher flow meters have a significantly lower pressure drop at same GPM. This is a 1" in line meter, charts on second page of link, see 16 GPM model under oil and water meters: http://www.hedland.com/resources/products/Page63-64-EZ-View_0.5-1inch_MetersRev2.pdf

Note that the 18 GPM model looks like only about 2.6 PSID drop at 12 GPM, maybe I'll try to switch to that meter before it ships!

With an instrumentation system like the WEL ( http://www.welserver.com ), and for maximum accuracy, you'll need something like this.  Something that has a pulse output stream that's representative of volume of water flow.

In my case, I assume a constant flow, that I have measured manually, since I don't have a flow meter installed.

Best regards,

Bill

 

Folks,

All of these systems have a built-in flow meter - the heat exchanger. All you need is the delta P across it and the pressure drop chart published by the manufacturer.

I would definitely avoid putting anything like an 8 PSID restriction in the loop. The one I've been debugging for my builder went from 3 PSID to 5 PSID with an extra pump added to the flow center.

I realize the usefulness of a pulse train or 4-20 output for data collection and performance monitoring, but I strongly suggest finding a way to derive it from the heat exchanger Delta-P

Agree completely on not adding a restrictive flowmeter. Look at it this way - 16gpmX8psi is 280 Watts with a 20% efficient pump, that's a big load to be running for hundreds or thousands of hours per year.

The pressure differential method is perfectly valid but is of limited accuracy if you are just going by manufacturer's tables. If you have very accurate pressure sensors and calibrate the flow vs. delta-P curve (a stopwatch with a bucket is a surprisingly accurate method of flow measurement) it can be very accurate. The main thing I don't like about this way of measuring flow is that you have no way to tell if your heat exchanger is getting scaled up, which is especially important in an open system. If it gets blocked up you could have significantly less flow at the same delta-P.

I'm using regular old nutating disc municipal style water meters for my flow measurement. The 1" sizes have relatively low flow restriction (less than 1 psi for 12gpm), and are very accurate over much of their range. They are relatively cheap and can be configured with a pulse output. So far I've been very happy with the results.

Thanks, yes I was surprised at how high the pressure drop was on that 16 GPM unit especially. I will reconsider... thanks for pointing out the issue Engineer!