Bulbs last longer than 4-6 months as was mentioned, its the sensor’s ability to read the strength that becomes the issue. We’ve had great success using Muratic Acid and a Qtip on the sensor glass which will extend the sensor life another 4-6 months at a time. Also instead of replacing the sleeve you can rotate it if its cloudy at the sensor input to try and get it to unlock the solenoid.

In the end most municipalities we service here opt for parallel installation regardless of brand because of the inherit flaw in reading UV strength through glass and water. Basically a manufacturer needs to make a lamp that has a sealed sleeve and lamp combination that has 1″ of lamp sealed outside the stream of water to sense the strength and that would solve the issue, but I’m sure the cost and heat of this would be a hurdle.

I believe a new bulb puts out more UV light than an older bulb, so in theory replacing the bulb should help. But the old bulb should be working well enough to kill any bacteria, as long as it hasn’t been in service for over a year.

Depending on your water source, removing & cleaning the outside of the glass sleeve really helps too. Our system is for filtered lake water (3 filters ahead of the UV light) & I’ve found that although the UV warning light doesn’t come on, I still have to clean the sleeve every 6 months for the coliform bacteria tests to come back negative. I wipe it with a cloth using a light bleach solution, but if you have hard water you’d have to use the scale remover which is what’s recommended in the Trojan manual.

BTW our neighbor (same lake water source) had been replacing their UV bulb annually but hadn’t ever cleaned the sleeve — when they tested their water, they got 220 for the coliform count & 25 for the e.coli count! They cleaned the sleeve, shocked everything downstream & so far that’s solved the problem.

Good luck

Does anybody know if a new bulb will make any difference to a water test even though all lights are green?

Installed 25 December 2009
commissioned when the house was completed and occupied 4 November 2010

The unit periodically started to beep back in May, 2011, only five months after starting the unit. Because you can never seem to get anyone at Water Doctor in Bangkok who can speak English, my Thai wife called and the lady she spoke to told her to clean the glass lens of the sensor. This did not solve the beeping problem so she called several more times and each time the lady would repeat the instructions to clean the glass sensor lens. Now common sense should have kicked in and when this lady received the third call from the same customer complaining about the same issue that lens cleaning did not solve, one would think that a real customer service rep would dig deeper into finding a solution rather than repeating the standard instructions to clean the lens. I told my wife to contact someone else in the Bangkok office. She contacted another lady who said she was traveling in northern Thailand and would contact the home office and get back to her with some answers. She never called back. When my wife tried to contact her again, it was discovered that she had gone abroad. Now it is August so the months have passed and nobody at Water Doctor seems to care enough about customers to return calls. She finally managed last week to speak to a man at the Bangkok office who could not give her a price quote on a new sensor nor could he give her a part number (missing from the owners manual for D4 Plus models) and price quote on a new UV lamp.

Since the Certificate of Calibration was signed by Silvance Molinari on 9 February 2009 I am assuming it is a D4 Plus 2009 model.

To silence the aggravating beeping noise I have unplugged the sensor which leads me to believe the sensor is the problem. But now I am reading the blog on blog.netscraps.com to learn that your UV Max C4 has the same problem and it turns out that the problem is defective power units were manufactured and sold all through 2009.

I really need some one to step up to the plate and contact me (English speaker) and explain how Trojan and Water Doctor are going to solve this beeping issue with my D4 Plus unit. Many foreigners are moving into my area of Thailand and they are all interested in water purification for their retirement homes. What would you like me to tell them when they contact me to come and look at the system that was installed in my home??

Regards
John W Luersen