Hi all I'm new to the forum and hope I can get some good advice for questions I have about properly setting up an exit water discharge manifold for an open loop system. I have spoken to many local installers and have received disparate and unclear advice. I have a Water Furnace, model ATV045D110CRT (installed in 1994) and, according to the manual, this unit should flow from 3-6 GPM on stage 1 and 6-9 GPM on stage 1 & 2 together. Currently, I have a square-shaped manifold made of PVC connected to the furnace discharge fitting where the water enters a tee, flows left through a solenoid valve for stage 1, and flows right into a second valve when stage 2 fires up. One big issue I have right now is a significant water hammer that occurs when the furnace shuts down or when stage 2 reverts to stage 1. I know this is from my use of standard, fast closing solenoid valves--these need to be replaced. So, with this background, here are my questions: 1. What would be a good, solid slow-closing solenoid valve to replace mine? My web research has led me to the Taco 5101-G2--they seem to be commonly used and effective. Am I on the right track here? 2. I noticed that the 5101-G2 has a flow rate of 4.5-6 GPM. Does anyone know what this really means? Does the valve somehow control the amount of flow going through, or am I missing something here. I'm thinking that having two of these for my system would allow enough flow for stage 1 alone and for stage 1 & 2 together. 3. I've been told that I probably want to install some flow-restrictors or "circuit-setters" or "ball valve regulators" to control the flow going through my system. Would you agree? If so, could you provide some recommendations on what, exactly, I should buy and where they would be installed in the plumbing? For example, up or downstream of the solenoid valves? 4. I've also been told that a flow meter would be useful--but the same questions apply here. What, exactly, would be a good product to buy? Where would it be installed? I'm assuming that the reasoning behind being able to control your flow is because you don't want to waste energy from your well pump. So, for my system, I assume it would be set for the minimum flow required for stage 1 that still prevents freeze-up, and the same would hold for stage 2. To be safe, I could set stage 1 for 6 GPM (which is the max flow of the Taco valve) and set stage 2 for an additional 3 GPM. Does this make sense, or am I missing something? Would you need a separate flow meter for each line? 5. Finally, I've read that installing a pressure reducer on the line going to your furnace is a good idea. Right now, the water line going to my furnace is at household pressure--about 60 PSI. Comments or advice on this? I know this is a lot and I apologize if these topics have been covered in part elsewhere. I hope to get solid advice on my entire discharge system so I can take action soon. This water hammer is making me very nervous. Thanks all Cheers Matt PS--any reason why you couldn't make your manifold out of PEX?
You are very much on the right track. I'll just add some clarification and issues from experience. The slow opening solenoid valves are commonly used. Taco as you mentioned. They don't seem to have the greatest durability though. It is important to ensure the compressor does not come on until valve is open. So a slow-opening zone valve with an end switch. The parallel header is common for the circuit you've mentioned. But you don't necessarily need to switch sides. You just add sides together to get the full flow required at 2nd stage. Allows you to reduce some costs in fittings. You would use flow-restrictors to get the exact flows you require. But, word of warning, when using a flow restrictor you should have a buttefly valve or such downstream of it. You use this to throttle the flow (create back pressure) as flow restrictors often create a bunch of noise without the back pressure. These are easy enough to source through a plumbing supplier to the flow rate you require. A flow meter is an option. A pool supplier in your area might be a good place to pick up one locally. Otherwise, using the P/T ports to measure pressure drop should be fine. A pressure reducer is almost mandatory if your system is also plumbed to your domestic water system. The standard domestic water pressure is too much for many 24V valves to close against. We fixed one system in which the well pump ran 24x7 for 3 years because of this issue. We were brought in when this, combined with high water, flooded the crawl space. So generally speaking you have: - inlet = pressure reducer - outlet x 2 = solenoid valve + flow restrictor + butterfly valve Iff your system is not tied in to the domestic, you only need the one solenoid valve as you will turn on/off the pump with hvac demands. It will always flow through the one side of the circuit and through the other when stage 2 is required. So the solenoid valve would go on the 2nd circuit. You can build this out of PEX as long as the pipe size allows adequate flows for what you require. Last but not least, you generally have some back pressure on the discharge line (see an irrigation/pump company for a pressure setting foot valve or such) that allows you to keep a column of water in your system. If it drained through each time, you will get noise, vibration, and unnecessary wear and tear on your equipment.
Hi Chris Thanks for the reply. A couple of questions. I did purchase a couple of Taco 5101-G2 valves. Felt I had to, just have too much water hammer. So that's done. Not quite getting the gist of adding the sides together to get the full flow at the second stage. Do you mean just having like a single line system with one valve? So if the valve opens for stage one, and X amount of flow goes through, when stage 2 kicks in, the valve will already be open? Please clarify if you can. in one of my original DIY installs, I put flow restrictors downstream of the solenoid valves. They were noisy, for sure. Also froze my system out, not enough flow I think, even though I think I sized them right. How would this system work if you just had one line, one solenoid? Again, I think I get it, just a bit unclear. My system is tied to my domestic so I guess a pressure reducer is needed. Never had one, but what the he k. I'll do it. Makes sense to me. regarding your last point, the main water exit line, where my dual manifold comes into one line, goes up my wall a bit, so I would assume it can't ever be empty. Anyway, your reply has been informative and helpful. I hope we can keep going so I gain the confidence to fix my system in the middle of winter! cheers matt
Your system is tied in to your domestic, so ignore my comments about only one solenoid. For 2nd stage, you don't need to close off one side of your circuit. You just have both sides open to give you flow. I would just simplify it to 2 x 5gpm flow restrictors. So you have 10gpm when both are open. To clarify, your flow restrictors are simply to stop you from unnecessarily wasting water. Your pump and plumbing are sized to give you adequate flow to the heat pump. Siphoning can still pull the water out of your manifold, even after it is shut off. But, you can tell if that is the case. Air = noise.
I see. How do you keep both solenoids open at the same time? I have four wires coming from my furnace, two for one valve, two for another. How would I wire to just keep both open? And, if I did this, wouldn't approx. 10 GPM be flowing all the time, regardless of what stages were activated? Finally, with your suggested 2x5 system, would I still need valves downstream of the flow restrictions? thanks Chris, I apologize for my naïveté.
Wiring is not really something I wanted to explain over the internet. The P.Eng. is Canadian. U.S. gets nasty about things when people hurt themselves. But something like Y1 opens one valve. Y2 opens both valves. Yes, valves downstream. If your flow restrictors don't make noise, you're a lucky man.
Hi Chris et al. Well, I'm finally getting around to implementing Chris's suggestions for my Water Furnace discharge manifold. And, as you might guess, I have just a few more questions. Here goes. 1. My system is tied into my household water line, thus it is at household pressure. Chris suggested I put in an in-line pressure reducer on the inlet side of my furnace. How much should I reduce my pressure? It is near 60 psi now, so half? Quarter? 2. I want to re-do my manifold in PEX, but we can't connect the PEX to the brass elbows with P/T ports on my furnace because those elbows 90 into a barbed, 1" fitting. My plumber says we need a 90 that elbows into a female thread. I can get a street 90 and tap some threads into it for the P/T ports. But, is there an easier solution? Doesn't someone make a red brass 90 with P/T ports that elbows into a female thread? Or, if not, where can I get the P/T ports? 3. Chris mentioned that I want the valves to open prior to the compressor starting, thus a slow-opening zone valve with an end switch. Earlier, I mentioned I bought the TACO 5101-G2 valves--are these "zone" valves and do they have an "end switch"? I guess that's all for now, very much appreciate any help you can offer. Cheers Matt
Taco makes a valve specific for geo. The fittings you are calling "elbows" on your heat pump are hose kit tees. You can A) remove the PT ports and purchase tees and fittings to your liking bushing the end of the tee down for the PT ports or B) use 1" hose off the barbed fitting and take it to another barb fitting that has desired threads. Your heat pump doesn't care about pressure just flow. you can pick whatever pressure you like, but I'd likely keep it no less than 15lbs or so (more of a boilerman habit than requirement).
1. Reduce it enough that the valves fully close and then a bit more to make sure. As Joe has said, I find this to be around 15-20 psi depending on valve. 2. Just build your own 90 out of brass/copper. 3. Yes, those are slow opening with an end switch.
Thanks all, appreciate the info. Should be tackling this project soon. Also stumbled upon a company called Flow Center Products, in Indiana, I think. They have lots of parts and fittings for geothermal devices. Has everything I need really. Again, thanks. Matt
I would be interested in any alternatives to the Taco geothermal valve. I have run an open loop system for 7 years, and my source water is good quality. I have gone through three Taco valves, which are a bit expensive. So from my perspective, they work, they are expensive and they don't last long. They do have switch contacts, so that you can assure an open valve before your compressor fires up.
