ScottH Posted October 10, 2010 Report Share Posted October 10, 2010 Hi there, I'm new to this forum and we recently purchased a swim spa in Australia with 2 gas heaters (1 for spa end & 1 for swim end). Everything was working fine for the first couple of months, however now when the low speed pump kicks in to heat (thus starting the heater), the heater ignites and starts to make a very loud whining sound. If I increase the pressure of the pump by increasing the speed, the sound goes away, but comes back again if I run the pump on low speed again. I don't think there is an air lock as I have bled the pump at the union but I don't know what else to do...? Unfortunately the company we purchased from has just gone into liquidation so I don't think a warranty claim is going to be an option... Any thoughts please...? Quote Link to comment Share on other sites More sharing options...
txpoolguy Posted October 10, 2010 Report Share Posted October 10, 2010 It's likely that you have an accumulation of "scale" inside the heater well or heat exchanger, depending on which model you have. It results in low water flow thru the heater, which overheats the water, turning it to steam, which is the noise you hear. You'll need to have a qualified heater technician come check it out & see if it's repairable (cleanable) or not. This is usually a result of elements in the water which collect on the inside of the heater well/exchanger as they become less soluble in water when heat is applied. Calcium is one of the most common elements that does this. Get your water checked as well, specifically the calcium and if they can, have them check your saturation index to see where your water stands. The heater manufacturer may be able to offer assistance, even though your dealer has failed. Quote Link to comment Share on other sites More sharing options...
Dr. Spa Posted October 10, 2010 Report Share Posted October 10, 2010 As you say the heater is "recently purchased", I doubt there's been enough time for calcium build-up. I more suspect a dirty filter, reducing the water flow. Quote Link to comment Share on other sites More sharing options...
Pool Clown Posted October 11, 2010 Report Share Posted October 11, 2010 It sounds like the water is at just the right velocity to "whistle" through one of the by-passes. If it only does this when the heater is firing, but stops when the heater is off, then i think it would be the thermal by-pass as opposed to the mechanical. Mechanical would do it all the time. Thermal wouldn't start doing it right away, maybe 10 sec or so after firing, giving the thermal time to slowly heat up, and slowly open to the right spot to whistle or whine. Could be a cool little alarm telling you that the filter has gotten a little dirtier that before. Not necessarily time to clean, just a little dirtier. Quote Link to comment Share on other sites More sharing options...
ScottH Posted October 11, 2010 Author Report Share Posted October 11, 2010 It's likely that you have an accumulation of "scale" inside the heater well or heat exchanger, depending on which model you have. It results in low water flow thru the heater, which overheats the water, turning it to steam, which is the noise you hear. You'll need to have a qualified heater technician come check it out & see if it's repairable (cleanable) or not. This is usually a result of elements in the water which collect on the inside of the heater well/exchanger as they become less soluble in water when heat is applied. Calcium is one of the most common elements that does this. Get your water checked as well, specifically the calcium and if they can, have them check your saturation index to see where your water stands. The heater manufacturer may be able to offer assistance, even though your dealer has failed. Thanks. I spoke to the Heater tech guy today and he mentioned that it was more than likely going to be a blocked filter or air in the lines, but unfortunately I have ran the pump without the filters in and done all I can to remove any possible air lock and the noise persists - now in both the spa and the pool (both heaters are separate), so that tells me that it probably is the chemical balance that has caused it. Really disappointing given that we only followed the instructions that the pool shop gave us, but it appears as though this may contradict what the heaters actually need to function correctly - eg when the heater tech came over, he mentioned that our water was hard (not sure how we can tell by just feeling it), but then he saw our most recent water test results and apparantly the alkaline is too low and the chlorine is too high... Do you think that could be the problem? If so, do you know what sort of balance we should be aiming for to ensure the heaters run smoothly? Many thanks...Scott Quote Link to comment Share on other sites More sharing options...
Pool Clown Posted October 11, 2010 Report Share Posted October 11, 2010 Does the heater bang and shake? or are you just hearing the sound? Actually, at this point, i think the heater should be looked at (header taken off to view the inside of the exchanger). Note: Even though your dealer went under (no pun), you should still be able to warranty heater through the manufacturer if it's only a couple of months. BUT if this turns out to be chemical imbalance, i don't think the manuf. will warranty. Quote Link to comment Share on other sites More sharing options...
ScottH Posted October 13, 2010 Author Report Share Posted October 13, 2010 Does the heater bang and shake? or are you just hearing the sound? Actually, at this point, i think the heater should be looked at (header taken off to view the inside of the exchanger). Note: Even though your dealer went under (no pun), you should still be able to warranty heater through the manufacturer if it's only a couple of months. BUT if this turns out to be chemical imbalance, i don't think the manuf. will warranty. Thanks....no shaking or banging, just the sound that starts to occur not long after it fires up...it's like a loud whining groaning noise. I'm getting the heater tech to come out this weekend to check it out, but I'm starting to think it has something to do with the chemical balance of the water because it didn't do it for the first few months or so, but has just started so you would think it's not a mechanical fault but something that has taken a little while to accumulate into a problem... Quote Link to comment Share on other sites More sharing options...
lowdenrw Posted November 19, 2010 Report Share Posted November 19, 2010 Does the heater bang and shake? or are you just hearing the sound? Actually, at this point, i think the heater should be looked at (header taken off to view the inside of the exchanger). Note: Even though your dealer went under (no pun), you should still be able to warranty heater through the manufacturer if it's only a couple of months. BUT if this turns out to be chemical imbalance, i don't think the manuf. will warranty. Thanks....no shaking or banging, just the sound that starts to occur not long after it fires up...it's like a loud whining groaning noise. I'm getting the heater tech to come out this weekend to check it out, but I'm starting to think it has something to do with the chemical balance of the water because it didn't do it for the first few months or so, but has just started so you would think it's not a mechanical fault but something that has taken a little while to accumulate into a problem... I haven't used my spa in a very long time and recently replaced the motor due to severe corrosion on the casing and windings. Now that it is replaced, the water appears to be moving through the heater, but after a few minutes of heating I am hearing a banging noise. Could this be caused by the low flow due to corrosion. It does have kind of a pop/bang noise. Any suggestions? Quote Link to comment Share on other sites More sharing options...
ScottH Posted November 21, 2010 Author Report Share Posted November 21, 2010 Does the heater bang and shake? or are you just hearing the sound? Actually, at this point, i think the heater should be looked at (header taken off to view the inside of the exchanger). Note: Even though your dealer went under (no pun), you should still be able to warranty heater through the manufacturer if it's only a couple of months. BUT if this turns out to be chemical imbalance, i don't think the manuf. will warranty. Thanks....no shaking or banging, just the sound that starts to occur not long after it fires up...it's like a loud whining groaning noise. I'm getting the heater tech to come out this weekend to check it out, but I'm starting to think it has something to do with the chemical balance of the water because it didn't do it for the first few months or so, but has just started so you would think it's not a mechanical fault but something that has taken a little while to accumulate into a problem... I haven't used my spa in a very long time and recently replaced the motor due to severe corrosion on the casing and windings. Now that it is replaced, the water appears to be moving through the heater, but after a few minutes of heating I am hearing a banging noise. Could this be caused by the low flow due to corrosion. It does have kind of a pop/bang noise. Any suggestions? Quote Link to comment Share on other sites More sharing options...
ScottH Posted November 21, 2010 Author Report Share Posted November 21, 2010 As it turned out, our heater noise was fixed by replacing the standard pipes with larger diameter ones which allows more water to flow through the heater. So in the end it was a flow problem and not a chemical inbalance or scale build up. Much better now. Cheers Quote Link to comment Share on other sites More sharing options...
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